1,3-dipolar cycloaddition to the Fe-N=C fragment. 17.1 diastereoselectivity with C2- and non-C2-symmetric chirally N-substituted α-diimine ligands, R*-N=C(H)-C(R′) =N-R* and C5H4N-2-C(R′)=N-R*, with dimethyl acetylenedicarboxylate (DMAD) and methyl propiolate (MP).

Article abstract of DOI:10.1021/om950922o

The 1,3-dipolar cycloaddition reaction of Fe[R*-DAB(H;H)](CO)₃ (6k; R*-DAB(H;H) = R*-N=C(H)-C(H)=N-R*) with dimethyl acetylenedicarboxylate (DMAD), in which the R*-DAB(H;H) ligand is C₂-symmetric and is chirally N-substituted, gives the two expected diastereomers with low diastereoselectivity, due to a small difference in the rate constants of the two reactive C=N groups in 6k exposing their re and si faces, respectively. The 1,3-dipolar cycloaddition reaction of Fe(α-diimine)(CO)₃ (1, 6m) with DMAD and methyl propiolate (MP), in which a non-C₂-symmetric α-diimine ligand (R*-DAB(H;Me) and Py-2-C(R′)=N-R* (R*,R′-PyCa) is chirally N-substituted, gives the two expected diastereomers with medium to high diastereoselectivity. The diastereoselectivity with the non-C₂-symmetric α-diimine ligands, which have only one reactive imino group, depends on the size of the chiral group R*, the distance of the chiral group to the reacting centers, and the type of dipolarophile. The two starting complexes (1 and 6m) exist in solution in the form of two - rapidly interconverting diastereomeric conformers I and II. In contrast to the C₂-symmetric case, the free energies of activation for the two different conformers and their respective concentrations may be quite different here. The diastereoselectivities could not be influenced by variation of temperature, solvent, or the additional ligand. Kinetic resolution by a cycloreversion reaction could be excluded by the use of a chiral additional ligand and an achiral α-diimine ligand (i-Pr, H-PyCa, or i-Pr-DAB(H; H)). X-ray crystal structures have been determined from the respective diastereomeric mixtures of the pyrrolinone complex 5cks and the [2.2.2] bicyclic product 7aks. The structures of the [2.2.2] bicyclic product 4aks and of the free pyrrolinone ligand 8als have been determined using diastereomerically pure products. The 5-(2-pyridyl)pyrrolin-2-one ligands 8 are decomplexed from their precursors 5 by Me₃NO, air oxidation, exchange by CO, and oxidative reactions with dihalogens or H₂O₂.

Full text of DOI:10.1021/om950922o

2148
Organometallics 1996, 15, 2148-2169
1,3-Dip ola r Cycloa d d ition to th e F esNdC F r a gm en t. 17.1
Dia ster eoselectivity w ith C2- a n d n on -C2-Sym m etr ic
Ch ir a lly N-Su bstitu ted r-Diim in e Liga n d s,
R*sNdC(H)sC(R′)dNsR* a n d C5H4N-2-C(R′)dNsR*, w ith
Dim eth yl Acetylen ed ica r boxyla te (DMAD) a n d Meth yl
P r op iola te (MP ). Decom p lexa tion of th e P yr r olin on e
Liga n d of F e(CO)3(p yr r olin on e) Com p lexes
Nantko Feiken, Pieter Schreuder, Ron Siebenlist, Hans-Werner Fru¨hauf,* and
Kees Vrieze
Laboratorium voor Anorganische Chemie, J . H. van ’t Hoff Research Instituut, Universiteit
van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
Huub Kooijman, Nora Veldman, and Anthony L. Spek†
Bijvoet Center for Biomolecular Research, Vakgroep Kristal- en structuurchemie, Universiteit
Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands
J an Fraanje and Kees Goubitz‡
Laboratorium voor Kristallografie, J . H. van ’t Hoff Instituut, Universiteit van Amsterdam,
Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
Received November 30, 1995X
The 1,3-dipolar cycloaddition reaction of Fe[R*-DAB(H;H)](CO)3 (6k ; R*-DAB(H;H) )
R*sNdC(H)sC(H)dNsR*) with dimethyl acetylenedicarboxylate (DMAD), in which the R*-
DAB(H;H) ligand is C2-symmetric and is chirally N-substituted, gives the two expected
diastereomers with low diastereoselectivity, due to a small difference in the rate constants
of the two reactive CdN groups in 6k exposing their re and si faces, respectively. The 1,3-
dipolar cycloaddition reaction of Fe(R-diimine)(CO)3 (1, 6m ) with DMAD and methyl
propiolate (MP), in which a non-C2-symmetric R-diimine ligand (R*-DAB(H;Me) and Py-2-
C(R′)dNsR* (R*,R′-PyCa) is chirally N-substituted, gives the two expected diastereomers
with medium to high diastereoselectivity. The diastereoselectivity with the non-C2-symmetric
R-diimine ligands, which have only one reactive imino group, depends on the size of the
chiral group R*, the distance of the chiral group to the reacting centers, and the type of
dipolarophile. The two starting complexes (1 and 6m ) exist in solution in the form of two
rapidly interconverting diastereomeric conformers I and II. In contrast to the C2-symmetric
case, the free energies of activation for the two different conformers and their respective
concentrations may be quite different here. The diastereoselectivities could not be influenced
by variation of temperature, solvent, or the additional ligand. Kinetic resolution by a
cycloreversion reaction could be excluded by the use of a chiral additional ligand and an
achiral R-diimine ligand (i-Pr, H-PyCa, or i-Pr-DAB(H; H)). X-ray crystal structures have
been determined from the respective diastereomeric mixtures of the pyrrolinone complex
5ck s and the [2.2.2] bicyclic product 7a k s. The structures of the [2.2.2] bicyclic product
4a k s and of the free pyrrolinone ligand 8a ls have been determined using diastereomerically
pure products. The 5-(2-pyridyl)pyrrolin-2-one ligands 8 are decomplexed from their
precursors 5 by Me3NO, air oxidation, exchange by CO, and oxidative reactions with
dihalogens or H2O2.
In tr od u ction
considerable synthetic effort in the last decades.2 Or-
ganotransition-metal complexes tuned with the right
ligand system are very useful, because of their signifi-
cant impact on synthetic organic chemistry and their
applications in the area of asymmetric induction. In the
production of chiral products, e.g., in the synthesis of
natural products as alkaloids, the Fe(CO)3 group has
The development of highly efficient and diastereose-
lective asymmetric cycloaddition reactions, e.g. Diels-
Alder reactions, for the construction of chiral interme-
diates in synthetic organic chemistry has attracted
* To whom correspondence should be addressed.
† Address correspondence pertaining to crystallographic studies (for
4a k s, 7bk s, and 8a ls) to this author.
‡ Address correspondence pertaining to crystallographic studies (for
5ck s) to this author.
(1) Part 16: Feiken, N.; Fru¨hauf, H.-W.; Vrieze, K.; Veldman, N.;
Spek, A. L. J . Organomet. Chem., in press.
(2) Oppolzer, W. Angew. Chem., Int. Ed. Engl. 1984, 23, 876.
X Abstract published in Advance ACS Abstracts, March 15, 1996.
0276-7333/96/2315-2148$12.00/0 © 1996 American Chemical Society

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2149
Sch em e 1. Rea ction Step s in th e Cycloa d d ition of
DMAD to th e F esNdC F r a gm en t in Com p lexes
F e(CO)3(iP r -DAB)
been shown to be very useful in controlling the regio-
and stereochemistry of, e.g., nucleophilic addition.3
The 1,4-diaza 1,3-diene ligand system, represented by
R*-DAB(H;R′),4 R*,R′-PyCa,4 bipyridine, and 1,10-
phenanthroline, with its good σ-donor and π-acceptor
properties and its versatile coordination behavior, has
long been known to stabilize a wide variety of transition
metals in low oxidation states.5 In catalytic systems it
is particularly useful for the ease with which it can be
tailored with respect to its electronic and steric proper-
ties and the rigidity5d,e or flexibility of its NdCsCdN
backbone.5 In addition, the ready availability of the
diaza dienes makes them attractive as reactive building
blocks for organic syntheses, e.g., for the formation of
nitrogen heterocycles in the coordination sphere of the
metal.
Over the last decade much research has been carried
out in our laboratory on the 1,3-dipolar cycloaddition
reactions of mononuclear M(R-DAB)(CO)3-n(R′-NC)n (M
) Fe, Ru, Mn; n ) 0, 1, 3) complexes with unsaturated
substrates.6
As was demonstrated in previous parts of this series
of articles,1,6 the product formation, for the type of
reactions shown in Scheme 1, is dependent on the
coligands, additional ligands (L), the metal, and the
substitutional pattern of both the DAB ligand and the
dipolarophile.
In the first step of this reaction sequence, a prochiral
sp2-hybridized imine carbon atom is converted in an
oxidative 1,3-dipolar cycloaddition reaction to a chiral
sp3-hybridized amino carbon atom. Under achiral reac-
tion conditions, the two expected enantiomers are
formed with equal probability. The isomer ratio may
differ from 1:1 if the conversion of the prochiral carbon
atom is done under chiral conditions. In the present
paper we report on the diastereoselectivity with C2- and
non-C2-symmetric chirally N-substituted R-diimine
ligands.
chiral N-substituents in the R-diimine ligands are
differentiated by the letters a -d , and the R′ groups are
denoted by the letters k -m , whereas the complexes
formed in the reaction with MP or DMAD bear the
letters r and s, respectively. The combination ik stands
for (S)-phenylethyl isocyanide as the additional ligand
and i-Pr, H-PyCa, or i-Pr-DAB(H; H) as the (achiral)
R-diimine ligand.
Resu lts a n d Discu ssion
If, in the text, one or more letters are omitted in a
compound number, e.g., 4k s or 5r (vide infra), we refer
to that compound type with all combinations of the
omitted letter; i.e., 4k s denotes the respective [2.2.2]
bicyclic complexes with all four different chiral groups
a -d , and 5r refers to all the pyrrolinone complexes 5
derived from methyl propiolate (r ) as dipolarophile.
Rea ctivity, Regioselectivity, a n d Ch em oselec-
tivity. The 1,3-dipolar cycloaddition reactions of the
present chiral Fe(R-diimine)(CO)3 complexes with DMAD
or MP under an atmosphere of CO, or in the presence
of another additional ligand L, lead in a HOMO-
controlled (type I)7 oxidative cycloaddition reaction to
the [2.2.1] bicyclic intermediate 2. From this intermedi-
ate the [2.2.2] bicyclic compounds of type 4 or 7 are
formed via insertion of one of the coordinated CO
ligands and an uptake of 1 equiv of L.
Gen er a l Con sid er a tion s. The employed ligands
and complexes are shown in Scheme 2. The type of
complex is identified by Arabic numbers. The different
(3) (a) Pearson, A. J . Pure Appl. Chem. 1983, 55, 1767. (b) Pearson,
A. J .; Ray, T. Tetrahedron 1985, 41, 5765.
(4) The 1,4-diaza-1,3-butadienes of formula R*sNdC(H)sC-
(R′)dNsR* are abbreviated as R*-DAB(H; R′). R*,R′-PyCa stands for
Py-2-C(R′)dNsR* (Py ) C5H4N); DMAD and MP stand for dimethyl
acetylenedicarboxylate and methyl propiolate, respectively.
(5) (a) van Koten, G.; Vrieze, K. Adv. Organomet. Chem. 1982, 21,
151. (b) Vrieze, K. J . Organomet. Chem. 1986, 300, 307. (c) Vrieze, K.;
van Koten, G. Inorg. Chim. Acta 1985, 100, 79. (d) van Asselt, R.;
Elsevier, C. J . J . Mol. Catal. 1991, 65, L13. (e) van Asselt, R.; Elsevier,
C. J .; Smeets, W. J . J .; Spek, A. L.; Benedix, R. Recl. Trav. Chim. Pays-
Bays 1994, 113, 88.
(6) (a) Part 1: Fru¨hauf, H.-W.; Seils, F.; Roma˜o, M. J .; Goddard, R.
J . Angew. Chem. 1983, 95, 1014; Angew. Chem., Suppl. 1983, 1435.
(b) Part 4: Fru¨hauf, H.-W.; Seils, F. J . Organomet. Chem. 1987, 323,
67. (c) Part 7: van Wijnkoop, M.; de Lange, P. P. M.; Fru¨hauf, H.-W.;
Vrieze, K.; Wang, Y.; Goubitz, K.; Stam, C. H. Organometallics 1992,
11, 3607. (d) Part 8: de Lange, P. P. M.; Fru¨hauf, H.-W.; Kraakman,
M. J . A.; van Wijnkoop, M.; Kranenburg, M.; Groot, A. H. J . P.; Vrieze,
K.; Fraanje, J .; Wang, Y.; Numan, M. Organometallics 1993, 12, 417.
(e) Part 11: de Lange, P. P. M.; de Boer, R. P.; van Wijnkoop, M.;
Ernsting, J . M.; Fru¨hauf, H.-W.; Vrieze, K.; Smeets, W. J . J .; Spek, A.
L.; Goubitz, K. Organometallics 1993, 12, 440. (f) Part 12: de Lange,
P. P. M.; Alberts, E.; van Wijnkoop, M.; Fru¨hauf, H.-W.; Vrieze, K.;
Kooijman, H.; Spek, A. L. J . Organomet. Chem. 1994, 465, 241. (g)
Part 14: Feiken, N.; Fru¨hauf, H.-W.; Vrieze, K.; Fraanje, J .; Goubitz,
K. Organometallics 1994, 13, 2825. (h) Part 15: van Wijnkoop, M.; de
Lange, P. P. M.; Fru¨hauf, H.-W.; Vrieze, K.; Smeets, W. J . J .; Spek, A.
L. Organometallics 1995, 14, 4781.
Depending on the dipolarophile used and the sub-
stituent on the imine carbon atom (R′) of the R*,R′-PyCa
ligands, the [2.2.2] bicyclic complexes 4 may or may not
be isolable. In the latter case the first observable
products are the pyrrolinone complexes 5. With MP as
(7) (a) Sustmann, R. Pure Appl. Chem. 1974, 40, 569. (b) Houk, K.
N.; Yamaguchi, K. In 1,3-Dipolar Cycloaddition Chemistry; Padwa, A.,
Ed.; Wiley: New York, 1984; Chapter 13.

2150 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
Sch em e 2. 1,3-Cycloa d d ition Rea ction s of DMAD a n d MP to Ch ir a l (r-d iim in e)F e(CO)3 Com p lexes a n d
Atom Nu m ber in g for NMR Assign m en tsa
a
The numbers of all compounds are given that appear in the text or in tables.
dipolarophile the first observed products, in a slow
selectivity;6b i.e., the unsubstituted acetylenic carbon
atom of MP becomes exclusively bonded to the iron
atom, and in the present case a single set of two
diastereomers is formed. The cycloaddition reaction of
DMAD and 6m shows a complete chemoselectivity6b for
the unsubstituted CdN group of the R*-DAB(H;Me)
ligand in 6m . The reactions were carried out at a
temperature range of -40 to +20 °C in different
solvents, but a dependence of the diastereomeric ratio
on the temperature or the solvent could not be observed.
In view of the Sustmann classification7 it is expected
that, for type I cycloaddition reactions, electron-donating
substituents on the 1,3-dipole will increase its reactivity.
However, with the Me group on the imine carbon atom
of the R*,R′-PyCa ligand (R′ ) Me) no acceleration of
the cycloaddition reaction was observed. This lack of
acceleration can be explained by steric hindrance for the
incoming dipolarophile, reducing the reaction rate. The
reaction rate in the case of R′ ) Ph is lowered as
expected, because the HOMO level of the 1,3-dipole is
lowered. Also, the reactions with MP are slower than
with DMAD, because there is only one electron-
withdrawing group present, and therefore the LUMO
level of the dipolarophile is at higher energy.
reaction, are the Fe(pyrrolinone)(CO)3 complexes 5r .
However, with R′ ) H and DMAD as dipolarophile, the
first stable products are the Fe(CO)3([2.2.2]bic) com-
plexes 4k s. The cycloaddition reaction with MP has a
higher energy barrier for the formation of the initial
[2.2.1] bicyclic complex 2. The reductive elimination
from the [2.2.2] bicyclic compounds 4 to the Fe(pyrroli-
none)(CO)3 complexes 5 probably has a lower activation
barrier for the MP reactions than for the DMAD
reactions (with R′ ) H). With R′ ) Ph or Me, indepen-
dent of the dipolarophile, the first observed and isolable
products are the Fe(pyrrolinone)(CO)3 complexes 5l,m ,
respectively.
The isolated [2.2.2] bicyclic complexes 4k s can be
converted to the corresponding Fe(pyrrolinone)(CO)3
complexes 5k s after several hours under 50 bar of CO
pressure at elevated temperatures. However, attempts
to convert the [2.2.2] bicyclic compounds 7s with L )
CO to the corresponding pyrrolinone complexes of type
5 by stirring a solution of 7s in a suitable solvent were
not successful. Even under high CO pressure and at
high temperatures, no conversion to complexes of type
5 could be observed. In earlier papers we reported6a
that the pyrrolinone complexes are easily obtained by
stirring the [2.2.2] bicyclic compounds in e.g. chloroform
or benzene with some silica gel. It appears that the
steric bulk of the chiral R* groups of the DAB ligands
somehow impedes the rearrangement of 7s into com-
plexes of type 5.
Decom plexation of th e P yr r olin on e Ligan d. Sev-
eral methods are available to liberate organic ligands
from their (transition) metal complexes.8 We tested
(8) (a) Franck-Neumann, M.; Heitz, M. P.; Martina, D. Tetrahedron
1983, 24, 1615. (b) Semmelhack, M. F.; Hall, H. T.; Farina, R.;
Yoshifuji, M.; Clark, G.; Bargor, T.; Hiratsu, K.; Clardy, J . J . Am.
Chem. Soc. 1979, 101, 3535. (c) Shvo, Y.; Hazum, E. J . Chem. Soc.,
Chem. Commun. 1974, 336.
As has been described earlier, cycloaddition reactions
with MP as dipolarophile show complete regio-

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2151
Ta ble 1. Dia ster eom er ic Ra tios Obta in ed w ith
DMAD a n d MP a s Dip ola r op h iles in Cycloa d d ition
Rea ction s w ith F e(CO)3(R*,R′-P yCa )
Ta ble 2. Dia ster eom er ic Ra tios Obta in ed w ith
DMAD a s Dip ola r op h ile in th e Cycloa d d ition
Rea ction s w ith F e(CO)3[R*-DAB(H, R′)
F igu r e 1. C2-Symmetric R*-DAB ligand.
the R′ group (for the chiral R*,R′-PyCa ligand and
DMAD, H > Ph > Me; for R*-DAB(H;R′), Me > H).
During the reductive elimination of the [2.2.2] bicyclic
complexes 4k s to the pyrrolinone complexes 5k s the
diastereomeric ratio remains unchanged. This means
that the diastereomeric ratios in the different isolated
products can be directly compared with each other. In
the case of 4bk s, the two diastereomers have sufficiently
different Rf values, and it was possible to separate the
two diastereomers by column chromatography on a
small column, by an appropriate selection of eluents.
The diastereoselectivity of the described cycloaddition
reactions was found to be independent of the tempera-
ture and of the polarity of the solvent (CH3CN, toluene,
THF, hexane). The diastereoselectivities with com-
plexes 1 and 6m are much higher than those with
complexes 6k . In 1 and 6m the R-diimine ligand is non-
C2-symmetric, whereas in 6k it is C2-symmetric. In the
following the differences between these two types with
respect to the diastereoselectivity will be discussed.
(a ) Th e C2-Sym m etr ic Ca se. The R*-DAB(H;H)
ligands are C2-symmetric (see Figure 1), because the
same chiral group is bonded to both nitrogen atoms of
the symmetrical DAB skeleton. In a square-pyramidal
coordination geometry, as depicted in Figure 2 for the
complex Fe[R*-DAB(H;H)](CO)3 (6k ), a rotation of the
R*-DAB ligand through 180° around its C2 axis (see
Figure 1) delivers an identical situation; i.e., there is
only one stereochemical form possible, and the iron atom
is not a chiral center.
some oxidative methods and one ligand exchange method.
In the oxidative methods, complexes 5l,m were treated
with I2, Cl2, H2O2, or air; also, the reaction with Me3-
NO was successful. Oxidative degradation when solu-
tions of 5 were stirred in air (with formation of iron
oxides) gave the best results, and for complexes with
R′ ) H it was the only useful method. Displacement of
the pyrrolinone ligand by CO with formation of Fe(CO)5
was successful for complexes 5l and 5m , with only
moderate yields, however.
Dia ster eoselectivity. The introduction of a chiral
N-substituent in the R-diimine ligand in the starting
compounds 1 and 6 induces diastereoselectivity in our
organometal cycloaddition reactions. The chiral R-di-
imine ligands are derived from chiral amines and
2-pyridinecarbaldehyde or (methyl) glyoxal. Some of
these Schiff base ligands have been used earlier9 in
order to study the optically active transition-metal
compounds after complexation of these ligands. The
R*,R′-PyCa ligands have been used in rhodium catalysts
in the enantioselective hydrosilylation of acetophenone
to give 1-phenylethanol in high optical yields.9b The
diastereoselectivities obtained with these ligands in the
present cycloaddition reactions with DMAD and MP are
summarized in Tables 1 and 2.
From Tables 1 and 2 it appears that the diastereo-
selectivity depends on the following: (1) the size of the
chiral group R*, (cHex)(Me)(H)C* > (Ph)(Me)(H)C* >
(Et)(Me)(H)C*; (2) the distance of the chiral center to
the reacting centers, (Et)(Me)(H)C* > (Et)(Me)(H)-
C*CH2; (3) the type of dipolarophile, DMAD > MP; (4)
When a dipolarophile approaches the square pyramid
in the C2-symmetric case (see Figure 2) from below, it
encounters the re face of one and the si face of the other
imino group in 6k . Attack of the re face of 6k gives a
different diastereomer (7k or 7k ′) than attack of the si
face of 6k , which gives the other diastereomer (7k ′ or
7k ). The si and re face of 6k have very similar
reactivities, and the diastereomeric ratio is therefore
caused by a small difference of the rate constants of
attack at the re and si faces. We found that the
(9) (a) Brunner, H. Acc. Chem. Res. 1979, 12, 250. (b) Brunner, H.;
Hermann, W. A. J . Organomet. Chem. 1973, 63, 339. (c) Brunner, H.;
Wachter, J .; Schmidbauer, J .; Sheldrick, G. M.; J ones, P. G. Angew.
Chem., Int. Ed. Engl. 1986, 25, 371. (d) Brunner, H.; Wachter, J .;
Schmidbauer, J .; Sheldrick, G. M.; J ones, P. G. Organometallics 1986,
5, 2212. (e) Brunner, H.; Reiter, B.; Riepl, G. Chem. Ber. 1984, 117,
1330.

2152 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
3, where the free energy of the system (vertical axis) is
set out against the reaction coordinate.
From the low observed diastereoselectivity with the
C2-symmetric diaza dienes, we have to conclude that the
free energies of activation ∆G‡ are of comparable size
for an attack of the dipolarophile on one or the other
CdN group, which exposes the re and si faces, respec-
tively; i.e., ∆Gq ≈ ∆Gqsi. We have to emphasize that
F igu r e 2. Square-pyramidal intermediate in the Berry
pseudorotation process with a C2-symmetric R-diimine
ligand. Of the two reactive imine groups, one exposes its
re face and the other its si face toward an incoming
dipolarophile.
re
there is only one 1,3-dipolar species present which at
the same time exposes reactive re and si faces. The
rates at which the two diastereomeric products are
formed depend only on the concentrations of the two
transition states (proportional to ∆Gqre and ∆Gqsi), since
the concentrations of the two reactive sites are inher-
diastereoselectivities in these cases are rather low (cf.
Table 2). Possible reaction profiles are shown in Figure
F igu r e 3. Reaction profiles for the reactions with the C2 and the non-C2 R-diimine ligands.

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2153
Table 1 shows different diastereoselectivities for the
reaction of specific PyCa complexes (combinations of R*
and R′) with the two dipolarophiles DMAD and MP. If
the diastereomer ratio (dr) in the products only depends
on the equilibrium position of the epimers I and II in
the starting complexes (case ii, vide supra), then we
should observe the same dr’s independent of the dipo-
larophile. From the different dr’s with the two dipo-
larophiles we can conclude that they react at different
rates with I and II; i.e., there is definitely a (small)
kinetic bias between the re and si faces, and the
observed dr’s are not a measure for the equilibrium
position I a II.
F igu r e 4. The starting diasteromeric conformers in com-
plexes 1 and 6m with non-C2-symmetric R-diimine ligands.
Of the two rapidly interconverting conformers, one exposes
the re face of the reactive imine group and the other the si
face toward an incoming dipolarophile.
There are strong steric interactions between the syn-
positioned C- and N-substituents of an imine group (R*
and R′);11 i.e., R′ influences the conformation of R*,
which in turn is reflected by differing dr’s for R′ ) H,
Me, Ph. In the cycloaddition reactions with DMAD, the
lowest diastereoselectivities are observed for R′ ) Me.
ently equal. The bulkiness of the R* group influences
the accessibility of the dipolarophile to the dipole. This
implies that one of the stereofaces reacts faster than
the other.
(b) Th e Non -C2-Sym m etr ic Ca se. There is an
obvious difference in the diastereoselectivity with the
C2- and non-C2-symmetric diaza diene ligand systems.
The achievable diastereoselectivities in the cycloaddition
reactions of complexes 1 and 6m are much higher than
those with the chiral C2-symmetric R-diimines. With
the non-C2-symmetric R-diimine ligands in 1 and 6m ,
which have only one reactive imino group in each
starting epimer, the central iron atom is also chiral, and
the starting complexes 1 and 6m exist in the form of
two (via Berry pseudorotation10) very rapidly equili-
brating epimers (with opposite configurations at the iron
atom) and are present in different stationary concentra-
tions according to their difference in free energy ∆G°I
- ∆G°II. In Figure 4 the epimers I and II are drawn in
the square-pyramidal conformation, which we think is
attacked by the dipolarophile from below.
The reaction of achiral Fe(R-diimine)(CO)3 (1ik and
6ik ) with DMAD in the presence of a chiral additional
ligand L gives the two expected diastereomers (4ik s and
7ik s, respectively) in a ratio of 1:1. Thus, at least under
the employed reaction conditions, the reversibility of the
cycloaddition reaction and consequent kinetic resolution
can be excluded. Obviously the activation barrier for
the retro-cycloaddition reaction is too high. This activa-
tion barrier may vary when other dipolarophiles and
ligands other than CO are employed in the starting
compound 6k , which we have described earlier.6e,g
Variation of the additional ligands L has no effect on
the diastereoselectivity of the cycloaddition reactions,
which is shown for the reaction of 1k and 6 with DMAD
in the presence of P(OMe)3 and t-Bu-NC instead of CO.
This is not surprising, because the additional ligand
reacts after the cycloaddition step with the unsaturated
[2.2.2] bicyclic intermediate 3 to give 4.
One of the epimers exposes the re face of the reactive
imine-carbon atom, while the other exposes its si face.
In such chiral complexes with unsymmetrical diaza
diene skeletons the two FesNdC fragments are inher-
ently chemically different and the attacking dipolaro-
phile in a 1,3-dipolar cycloaddition reaction has a strong
chemoselectivity;6b i.e., only the unsubstituted R-diimine
group is reactive. Unfortunately, we cannot conclu-
sively explain the high diastereoselectivities in this case.
As opposed to the C2-symmetric case, the free energies
of activation and the concentrations of the two different
diastereomeric 1,3-dipolar species I and II may be quite
different here. Any of three cases may prevail. (i) The
major (or only) diastereomer of the product is produced
at a (much) faster rate because the activation energy
∆Gqmaj is much lower than ∆Gqmin. Then any stationary
concentration difference is overruled and rendered
In all the cycloaddition reactions described in this
paper, we find no solvent or temperature effects on the
diastereoselectivity of the reaction. It is not very
surprising that the solvent polarity does not influence
the diastereroselectivity of the cycloaddition reaction,
because the two transition states resulting from attack
of either the re or si face cannot possess very different
polarities. In the non-C2-symmetric case the tempera-
ture should influence the equilibrium between I and II,
and thus, if case ii applies, also the diastereoselectivity.
However, in the relatively small temperature range in
which the reaction can be run (238 K e T e 298 K), we
did not find such an effect.
Cr ysta l Str u ctu r e of th e Com p lex 4a k s. The
molecular structure of complex 4a k s together with the
atomic numbering is shown in Figure 5. Bond lengths
and bond angles are given in Tables 3 and 4, respec-
tively.
unimportant. (ii) ∆Gqmaj and ∆Gq
are of comparable
min
size, but I and II are present in very different stationary
concentrations. This would mean that the diastereo-
selectivity is governed by thermodynamics, namely ∆G°I
- ∆G°II. (iii) Both a low activation energy and a high
The reaction leading to 4a k s is highly diastereo-
selective (100:0), giving only one diastereomer (cf. Table
1). The configuration of the former prochiral imine
carbon atoms C(14) and C(7) of the R* group is S. The
configuration of the chiral iron atom is OC-6-24-C,
according to the Baird-Cook-Sloan modification of the
stationary concentration work together, e.g. ∆Gq
<
maj
∆Gq
and [I] . [II] (cf. Figure 3).
min
The Berry pseudorotation in 1 and 6 is too fast to
observe the two diastereomers separately on the NMR
time scale, even at the lowest possible temperatures.
(10) Berry, R. S. J . Chem. Phys. 1960, 32, 933.
(11) Fru¨hauf, H.-W.; Breuer, J . J . Organomet. Chem. 1986, 301, 183.

2154 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
F igu r e 5. ORTEP plot of 4a k s at the 30% probability
level. Hydrogen atoms are omitted for clarity.
Ta ble 3. Bon d Dista n ces (Å) of th e Non -Hyd r ogen
Atom s of Com p lex 4a k s (Esd ’s in P a r en th eses)
Fe(1) -N(1)
Fe(1)-C(1)
Fe(1)-C(2)
Fe(1)-C(3)
Fe(1)-C(4)
Fe(1)-C(9)
O(1)-C(1)
O(2)-C(2)
O(3)-C(3)
O(4)-C(5)
O(5)-C(5)
O(5)-C(6)
O(6)-C(11)
O(7)-C(11)
O(7)-C(12)
O(8)-C(9)
N(1)-C(21)
N(1)-C(25)
N(2)-C(7)
2.023(12)
1.870(15)
1.792(15)
1.851(13)
2.001(13)
2.028(13)
1.108(19)
1.120(19)
1.142(16)
1.233(15)
1.365(17)
1.432(19)
1.172(17)
1.322(17)
1.45(2)
N(2)-C(9)
1.338(18)
1.464(17)
1.409(18)
1.348(18)
1.53(2)
N(2)-C(14)
C(4)-C(5)
F igu r e 6. ORTEP plot of 5ck s at the 50% probability
level. Hydrogen atoms are omitted for clarity.
C(4)-C(10)
C(7)-C(8)
Ta ble 4. Bon d An gles (d eg) of th e Non -Hyd r ogen
Atom s of Com p lex 4a k s (Esd ’s in P a r en th eses)
C(7)-C(15)
C(10)-C(11)
C(10)-C(14)
C(14)-C(25)
C(15)-C(16)
C(15)-C(20)
C(16)-C(17)
C(17)-C(18)
C(18)-C(19)
C(19)-C(20)
C(21)-C(22)
C(22)-C(23)
C(23)-C(24)
C(24)-C(25)
1.51(2)
1.551(19)
1.500(18)
1.501(19)
1.52(2)
1.53(2)
1.53(3)
1.50(3)
1.53(2)
1.53(3)
1.33(2)
N(1)-Fe(1)-C(1)
N(1)-Fe(1)-C(2)
N(1)-Fe(1)-C(3)
N(1)-Fe(1)-C(4)
N(1)-Fe(1)-C(9)
C(1)-Fe(1)-C(2)
C(1)-Fe(1)-C(3)
C(1)-Fe(1)-C(4)
C(1)-Fe(1)-C(9)
C(2)-Fe(1)-C(3)
C(2)-Fe(1)-C(4)
C(2)-Fe(1)-C(9)
C(3)-Fe(1)-C(4)
C(3)-Fe(1)-C(9)
C(4)-Fe(1)-C(9)
C(5)-O(5)-C(6)
C(11)-O(7)-C(12)
Fe(1)-N(1)-C(21)
Fe(1)-N(1)-C(25)
91.2(6)
169.9(5)
93.7(5)
88.5(5)
88.1(5)
92.7(7)
94.7(6)
174.6(5)
86.2(6)
95.2(6)
86.7(6)
82.9(6)
90.8(5)
178.0(6)
88.3(5)
O(4)-C(5)-O(5)
O(4)-C(5)-C(4)
O(5)-C(5)-C(4)
N(2)-C(7)-C(8)
N(2)-C(7)-C(15)
C(8)-C(7)-C(15)
Fe(1)-C(9)-O(8)
Fe(1)-C(9)-N(2)
O(8)-C(9)-N(2)
C(4)-C(10)-C(11)
C(4)-C(10)-C(14)
121.2(12)
126.8(13)
111.8(10)
108.4(13)
114.2(11)
115.7(12)
122.3(10)
116.7(9)
1.244(18)
1.354(18)
1.356(17)
1.485(15)
120.9(12)
125.6(12)
119.1(11)
1.39(2)
1.38(2)
1.35(2)
C(11)-C(10)-C(14) 115.3(11)
O(6)-C(11)-O(7)
O(6)-C(11)-C(10)
O(7)-C(11)-C(10)
125.5(14)
124.6(13)
109.9(11)
CIP rules.12 The total configuration of 4a k s as shown
in Figure 5 is OC-6-24-C-(S),(S).
116.4(11) N(2)-C(14)-C(10) 111.7(12)
114.5(12) N(2)-C(14)-C(25) 110.2(11)
123.6(10) C(10)-C(14)-C(25) 109.2(10)
The molecular structure of complex 4a k s has the
familiar [2.2.2] bicyclic skeleton that has been found
earlier.6e-g The geometry around the metal atom is
slightly distorted octahedral. The mean angles around
the chiral atom C(14) (110°) are characteristic for sp3
hybridization.
Cr ysta l Str u ctu r e of th e Com p lex 5ck s. The
molecular structure of the complex 5ck s together with
the atomic numbering is shown in Figure 6. Bond
lengths and bond angles are given in Tables 5 and 6,
respectively.
From the data set it is not clear if the given structure,
shown in Figure 6, represents the major diastereomer.
The diastereomeric ratio (62:38) found in the bulk of
the crystals by 1H NMR is the same as in the crude
reaction mixture of 5ck s. This means that no fractional
crystallization of one of the diastereomers had occurred.
Molecules of 5ck s contain two rings, which coordinate
to the iron atom via the nitrogen atom (N(1)) of the
pyridine ring and via the C(7)-C(8) double bond of the
pyrrolinone ring. The two rings are connected by the
chiral former imine carbon atom C(6). The configura-
tion of both chiral carbon atoms C(6) and C(14) is S.
119.2(9)
C(7)-C(15)-C(16)
110.1(12)
111.2(13)
C(21)-N(1)-C(25) 117.1(12) C(7)-C(15)-C(20)
C(7)-N(2)-C(9)
C(7)-N(2)-C(14)
C(9)-N(2)-C(14)
Fe(1)-C(1)-O(1)
Fe(1)-C(2)-O(2)
Fe(1)-C(3)-O(3)
Fe(1)-C(4)-C(5)
Fe(1)-C(4)-C(10)
C(5)-C(4)-C(10)
123.0(11) C(16)-C(15)-C(20) 110.2(13)
117.5(11) C(15)-C(16)-C(17) 110.9(13)
118.8(10) C(16)-C(17)-C(18) 114.7(15)
172.1(15) C(17)-C(18)-C(19) 111.3(16)
177.3(13) C(18)-C(19)-C(20) 110.2(14)
174.3(13) C(15)-C(20)-C(19) 112.7(13)
118.2(9)
116.2(9)
N(1)-C(21)-C(22) 124.7(15)
C(21)-C(22)-C(23) 118.6(15)
125.2(12) C(22)-C(23)-C(24) 117.4(14)
C(23)-C(24)-C(25) 121.4(13) N(1)-C(25)-C(24) 120.8(13)
N(1)-C(25)-C(14) 114.9(12) C(14)-C(25)-C(24) 124.2(12)
The configuration of the chiral iron atom is TB-5-12-A,
according to the Baird-Cook-Sloan modification of the
CIP rules.12 The total configuration of the diastereomer
given in Figure 6 is TB-5-12-A-(S),(S). The long bond
distance of the olefinic carbon atoms C(7)-C(8) of
1.444(8) Å is caused by the coordination to Fe(CO)3 and
indicates partial rehybridization sp2 f sp3 of the atoms.
Cr ysta l Str u ctu r e of th e Com p lex 7a k s. The
crystal structure of complex 7a k s together with the
atomic numbering is shown in Figure 7. Bond lengths
and angles are given in Tables 7 and 8, respectively.
Molecules of 7a k s have a [2.2.2] bicyclic structure in
which the bridgehead positions are occupied by the iron
atom and the chiral former imine carbon atom (C(14)).
(12) (a) Brown, M. F.; Cook, B. R.; Sloan, T. E. Inorg. Chem. 1975,
14, 1273. (b) Brown, M. F.; Cook, B. R.; Sloan, T. E. Inorg. Chem. 1975,
14, 1563. (c) IUPAC Nomenclature of Inorganic Chemistry Recom-
mendations 1990; Blackwell Scientific Publications: Oxford, 1990.

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2155
Ta ble 7. Bon d Dista n ces (Å) for Com p ou n d 7a k s
Fe(1)-N(1)
Fe(1)-C(1)
Fe(1)-C(2)
Fe(1)-C(3)
Fe(1)-C(4)
Fe(1)-C(9)
O(1)-C(1)
O(2)-C(2)
O(3)-C(3)
O(4)-C(5)
O(4)-C(6)
O(5)-C(5)
O(6)-C(11)
O(7)-C(11)
O(7)-C(12)
O(8)-C(9)
N(1)-C(7)
N(1)-C(13)
N(2)-C(9)
N(2)-C(14)
N(2)-C(17)
2.011(7)
C(4)-C(5)
1.454(11)
1.344(12)
1.544(13)
1.525(11)
1.496(12)
1.531(13)
1.483(12)
1.539(12)
1.524(13)
1.557(14)
1.500(13)
1.552(12)
1.500(13)
1.518(13)
1.504(16)
1.547(14)
1.511(13)
1.524(14)
1.531(15)
1.547(13)
1.517(13)
1.779(11)
1.792(10)
1.826(8)
2.014(9)
2.002(8)
C(4)-C(10)
C(7)-C(8)
C(7)-C(15)
C(10)-C(11)
C(10)-C(14)
C(13)-C(14)
C(15)-C(24)
C(15)-C(28)
C(16)-C(17)
C(17)-C(18)
C(18)-C(19)
C(18)-C(23)
C(19)-C(20)
C(20)-C(21)
C(21)-C(22)
C(22)-C(23)
C(24)-C(25)
C(25)-C(26)
C(26)-C(27)
C(27)-C(28)
1.167(13)
1.128(12)
1.139(11)
1.355(11)
1.433(10)
1.196(11)
1.199(10)
1.352(11)
1.423(12)
1.258(11)
1.493(11)
1.268(11)
1.348(12)
1.459(12)
1.476(10)
F igu r e 7. Molecular structure of complex 7a k s.
Ta ble 5. Bon d Dista n ces of th e Non -Hyd r ogen
Atom s (Å) of Com p lex 5ck s (Esd ’s in P a r en th eses)
Ta ble 8. Bon d An gles (d eg) for Com p ou n d 7a k s
N(1)-Fe(1)-C(1)
N(1)-Fe(1)-C(2)
N(1)-Fe(1)-C(3)
N(1)-Fe(1)-C(4)
N(1)-Fe(1)-C(9)
C(1)-Fe(1)-C(2)
C(1)-Fe(1)-C(3)
C(1)-Fe(1)-C(4)
C(1)-Fe(1)-C(9)
C(2)-Fe(1)-C(3)
C(2)-Fe(1)-C(4)
C(2)-Fe(1)-C(9)
C(3)-Fe(1)-C(4)
C(3)-Fe(1)-C(9)
C(4)-Fe(1)-C(9)
C(5)-O(4)-C(6)
C(11)-O(7)-C(12)
Fe(1)-N(1)-C(7)
Fe(1)-N(1)-C(13)
C(7)-N(1)-C(13)
C(9)-N(2)-C(14)
C(9)-N(2)-C(17)
C(14)-N(2)-C(17)
Fe(1)-C(1)-O(1)
Fe(1)-C(2)-O(2)
Fe(1)-C(3)-O(3)
Fe(1)-C(4)-C(5)
Fe(1)-C(4)-C(10)
C(5)-C(4)-C(10)
92.7(4)
172.6(4)
90.7(4)
88.9(3)
87.4(3)
90.4(5)
94.5(4)
173.0(4)
85.5(4)
95.8(4)
87.3(4)
86.2(4)
92.4(4)
178.0(4)
87.7(3)
114.3(7)
113.9(7)
122.5(5)
118.9(6)
118.5(7)
117.8(7)
122.9(8)
118.6(7)
C(24)-C(25)-C(26) 112.1(9)
C(25)-C(26)-C(27) 110.9(8)
C(26)-C(27)-C(28) 110.4(8)
C(15)-C(28)-C(27) 112.7(8)
Fe-C(7)
2.033(6)
2.068(6)
1.778(7)
1.812(8)
1.808(8)
2.040(5)
1.38(1)
1.352(9)
1.38(1)
1.39(1)
1.383(9)
1.488(8)
1.350(8)
1.547(8)
1.476(8)
1.444(8)
1.457(9)
1.485(9)
C(8)-C(12)
C(9)-N(2)
1.512(9)
1.367(8)
1.231(8)
1.209(9)
1.342(8)
1.45(1)
1.214(9)
1.312(8)
1.46(1)
1.51(1)
1.60(1)
1.455(9)
1.46(2)
1.140(9)
1.15(1)
1.13(1)
1.73(2)
1.65(2)
Fe-C(8)
Fe-C(18)
Fe-C(19)
Fe-C(20)
Fe-N(1)
C(9)-O(5)
C(10)-O(1)
C(10)-O(2)
C(11)-O(2)
C(12)-O(3)
C(12)-O(4)
C(13)-O(4)
C(14)-C(15)
C(14)-C(17)
C(14)-N(2)
C(15)-C(16)
C(18)-O(18)
C(19)-O(19)
C(20)-O(20)
C(1s)-Cl(1s)
C(1s)-Cl(2s)
O(4)-C(5)-O(5)
O(4)-C(5)-C(4)
O(5)-C(5)-C(4)
N(1)-C(7)-C(8)
N(1)-C(7)-C(15)
C(8)-C(7)-C(15)
Fe(1)-C(9)-O(8)
Fe(1)-C(9)-N(2)
O(8)-C(9)-N(2)
C(4)-C(10)-C(11)
C(4)-C(10)-C(14)
124.0(7)
110.7(7)
124.8(8)
108.7(7)
110.8(7)
114.3(7)
122.3(6)
117.5(6)
120.0(7)
120.8(8)
117.9(8)
C(1)-C(2)
C(1)-N(1)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
C(5)-C(6)
C(5)-N(1)
C(6)-C(7)
C(6)-N(2)
C(7)-C(8)
C(7)-C(10)
C(8)-C(9)
C(11)-C(10)-C(14) 121.2(7)
O(6)-C(11)-O(7)
O(6)-C(11)-C(10)
O(7)-C(11)-C(10)
N(1)-C(13)-C(14)
N(2)-C(14)-C(10)
N(2)-C(14)-C(13)
122.8(8)
125.8(8)
111.4(7)
118.9(8)
110.0(7)
110.1(7)
Ta ble 6. Bon d An gles (d eg) of th e Non -Hyd r ogen
Atom s of Com p lex 5ck s (Esd ’s in P a r en th eses)
C(10)-C(14)-C(13) 108.6(7)
C(7)-Fe-C(8)
C(7)-Fe-C(18)
C(7)-Fe-C(19)
C(7)-Fe-C(20)
C(7)-Fe-N(1)
C(8)-Fe-C(18)
C(8)-Fe-C(19)
C(8)-Fe-C(20)
C(8)-Fe-N(1)
C(18)-Fe-C(19)
C(18)-Fe-C(20)
41.2(2)
98.0(3)
137.8(3)
114.1(3)
82.4(2)
91.6(3)
97.8(3)
154.2(3)
97.1(2)
91.2(4)
84.0(3)
Fe-C(8)-C(7)
68.1(3)
117.7(4)
123.3(5)
108.9(5)
120.8(5)
111.1(5)
108.0(5)
25.5(6)
176.0(10) C(7)-C(15)-C(24)
113.7(7)
111.4(7)
Fe-C(8)-C(9)
176.9(9)
177.9(8)
122.3(6)
116.6(6)
121.1(8)
C(7)-C(15)-C(28)
Fe-C(8)-C(12)
C(7)-C(8)-C(9)
C(7)-C(8)-C(12)
C(9)-C(8)-C(12)
C(8)-C(9)-N(2)
C(8)-C(9)-O(5)
N(2)-C(9)-O(5)
C(7)-C(10)-O(1)
C(7)-C(10)-O(2)
C(24)-C(15)-C(28) 108.9(7)
N(2)-C(17)-C(16)
N(2)-C(17)-C(18)
110.1(7)
112.4(7)
C(16)-C(17)-C(18) 114.7(8)
C(17)-C(18)-C(19) 110.8(7)
C(19)-C(20)-C(21) 110.3(8)
C(20)-C(21)-C(22) 110.5(10) C(17)-C(18)-C(23) 111.3(8)
126.3(6)
124.7(6)
112.6(5)
C(21)-C(22)-C(23) 110.8(8)
C(18)-C(23)-C(22) 112.8(9)
C(15)-C(24)-C(25) 111.7(8)
C(19)-C(18)-C(23) 109.7(8)
C(18)-C(19)-C(20) 113.6(7)
The bond angles around C(14) are indicative of sp3
hybridization. The coordination geometry around the
iron atom is slightly distorted octahedral. Interesting
to note is the extremely short intramolecular contact
(3.080(11) Å) for C(13) to O(8), possibly indicating a
weak NdCsH‚‚‚OdC interaction. Similar examples of
such short intramolecular contacts have been found in
the literature.12,13
In the molecular structure shown in Figure 7, the
configuration of the chiral carbon atom C(14) is R, and
the configuration of the iron atom is OC-6-24-A, accord-
ing to the Baird-Cook-Sloan modification of the CIP
rules.12 The total configuration of this diastereomer is
OC-6-24-A-(R),(S),(S), in which the last two chirality
symbols stand for the configuration of the chiral R*
groups of the R*-DAB ligand.
The diastereomeric ratio found in the crude product
mixture of 7a k s is the same as that found in the bulk
of the crystals, as was shown with 1H NMR, which
means that no fractional crystallization of one of the
diastereomers had occurred during the crystallization.
Cr ysta l Str u ctu r e of th e Com p ou n d 8a ls.
A
crystal structure determination was carried out for the
organic compound 8a ls. Figure 8 gives the ORTEP
representation and the atomic numbering. Bond lengths
and angles are given in Tables 9 and 10, respectively.
A 1H NMR spectrum of the crystal batch, which was
used for the structure determination, showed that this
batch contained only one diastereomer! The diastereo-
selectivity of the cycloaddition reaction was 98:2. After
(13) Kulpe, S.; Seidel, I.; Geissler, G.; Tomaschewski, G. Cryst. Res.
Technol. 1982, 17, 91.
(14) Miller, R. D.; Theis, W.; Heilig, G.; Kirchmeyer, S. J . Org. Chem.
1991, 56, 1453.

2156 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
tion, due to the absence of heavy atoms and the presence
of a solvent area for which no discrete model could be
refined. The known configuration of C(7) of the R*
group, however, is S. The configuration of the new
chiral carbon atom (C(16)) is thus R.
The unit cell in the crystal contains four voids with a
volume and electron count one would expect for an ether
molecule of solvation. The correct elemental analysis
of 8a ls (without solvent; cf. Table 16) has been done of
a sample from the same batch as the structure deter-
mination; however, for homogeneity, it had been ground,
which has obviously led to the evaporation of all solvent
ether present in the crystals. Obviously the ether
molecules sit very loosely in the lattice (disorder, easy
evaporation) and therefore could not be refined.
The C(10)-C(13) distance of 1.328(2) Å is now in the
normal range of free alkenes (ca. 1.34 Å). The crystal
structure shows that H(6) of the cyclohexyl group is
pointed toward the π-electron cloud of the pyridine ring.
The anisotropy effect of the pyridine ring is reflected in
F igu r e 8. ORTEP plot of 8a ls at the 30% probability level.
Hydrogen atoms are omitted for clarity
Ta ble 9. Bon d Dista n ces of th e Non -Hyd r ogen
Atom s (Å) of Com p lex 8a ls (Esd ’s in P a r en th eses
1
the H NMR spectrum of 8a ls (vide infra).
NMR Sp ectr oscop y. The 1H and 13C{1H} NMR
data for the complexes 1 and 6 are listed in Tables 11
and 12, respectively; those for complexes 4, 5, and 7 and
for compound 8 are listed in Tables 13 and 14, respec-
tively; the atom numbering for all complexes is given
in Scheme 2.
O(1)-C(9)
O(2)-C(11)
O(3)-C(11)
O(3)-C(12)
O(4)-C(14)
O(5)-C(14)
O(5)-C(15)
N(1)-C(7)
N(1)-C(9)
N(1)-C(16)
N(2)-C(23)
N(2)-C(27)
C(1)-C(2)
C(1)-C(6)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
C(5)-C(6)
C(6)-C(7)
1.218(2)
1.197(2)
1.320(2)
1.455(3)
1.205(2)
1.327(2)
1.442(3)
1.473(2)
1.368(2)
1.4821(18)
1.3387(18)
1.338(2)
1.516(4)
1.530(3)
1.483(5)
1.537(5)
1.518(4)
1.485(3)
1.532(2)
C(7)-C(8)
1.532(3)
1.484(2)
1.492(2)
1.328(2)
1.482(2)
1.524(2)
1.534(2)
1.5315(19)
1.384(2)
1.394(2)
1.378(3)
1.372(4)
1.370(3)
1.384(3)
1.381(2)
1.387(2)
1.368(3)
1.378(3)
C(9)-C(10)
C(10)-C(11)
C(10)-C(13)
C(13)-C(14)
C(13)-C(16)
C(16)-C(17)
C(16)-C(23)
C(17)-C(18)
C(17)-C(22)
C(18)-C(19)
C(19)-C(20)
C(20)-C(21)
C(21)-C(22)
C(23)-C(24)
C(24)-C(25)
C(25)-C(26)
C(26)-C(27)
1H a n d 13C NMR of 1 a n d 6. The spectra of
complexes 1 and 6 show great resemblance to the
spectra of the corresponding free ligands and to the
earlier reported Fe(R-diimine)(CO)3 complexes.6,15 For
the diastereomeric mixtures of complexes 1 and 6m only
1
one set of H resonances is observed. The 13C NMR
spectra show only one resonance for the CO ligands,
indicative of scrambling of these ligands15 via a fast
Berry pseudorotation process.10
1H NMR of 4, 5, 7, a n d 8. Enantiomers under
achiral conditions have identical NMR spectra. How-
ever, mixtures of two diastereomers as well as the two
diastereomeric pairs of enantiomers do not give the
Ta ble 10. Bon d An gles (d eg) of th e Non -Hyd r ogen
Atom s of Com p lex 8a ls (Esd ’s in P a r en th eses)
1
C(11)-O(3)-C(12) 115.77(16) C(18)-C(17)-C(22) 117.86(14)
same H NMR spectra as, e.g., was observed for R* )
C(10)-C(13)-C(16) 110.54(13) N(1)-C(7)-C(6)
112.83(13)
(()-sec-Bu. In that case four stereoisomers were formed
in the cycloaddition reaction, i.e., two diastereomers and
the two enantiomers of these diastereomers. Accord-
C(14)-O(5)-C(15) 116.57(15) C(17)-C(18)-C(19) 121.43(18)
C(14)-C(13)-C(16) 121.07(12) N(1)-C(7)-C(8) 112.25(15)
126.50(13) C(18)-C(19)-C(20) 120.2(2)
124.18(15) C(6)-C(7)-C(8) 113.60(15)
121.36(11) C(19)-C(20)-C(21) 119.3(2)
127.53(15)
112.12(12) C(20)-C(21)-C(22) 121.04(19)
O(5)-C(14)-C(13) 111.36(14) O(1)-C(9)-C(10) 126.06(15)
C(23)-N(2)-C(27) 117.51(13) C(17)-C(22)-C(21) 120.15(16)
N(1)-C(16)-C(13) 101.09(10) N(1)-C(9)-C(10) 106.41(13)
C(2)-C(1)-C(6) 111.5(3) N(2)-C(23)-C(16) 114.15(11)
N(1)-C(16)-C(17) 111.54(11) C(9)-C(10)-C(11) 121.49(14)
C(1)-C(2)-C(3) 111.0(3) N(2)-C(23)-C(24) 122.34(13)
N(1)-C(16)-C(23) 108.05(10) C(9)-C(10)-C(13) 109.77(13)
C(2)-C(3)-C(4) 111.2(3) C(16)-C(23)-C(24) 123.27(12)
C(13)-C(16)-C(17) 107.64(11) C(11)-C(10)-C(13) 128.69(15)
C(3)-C(4)-C(5) 110.8(3) C(23)-C(24)-C(25) 119.45(15)
C(13)-C(16)-C(23) 111.82(11) O(2)-C(11)-O(3) 124.91(17)
C(4)-C(5)-C(6) 111.7(2) C(24)-C(25)-C(26) 118.25(17)
C(17)-C(16)-C(23) 115.74(11) O(2)-C(11)-C(10) 123.86(17)
C(1)-C(6)-C(5) 109.35(18) C(25)-C(26)-C(27) 119.13(17)
C(16)-C(17)-C(18) 120.75(13) O(3)-C(11)-C(10) 111.22(15)
C(1)-C(6)-C(7) 110.97(16) N(2)-C(27)-C(26) 123.31(16)
C(16)-C(17)-C(22) 121.19(13) C(10)-C(13)-C(14) 128.34(14)
C(5)-C(6)-C(7) 116.14(17)
C(7)-N(1)-C(9)
O(4)-C(14)-O(5)
C(7)-N(1)-C(16)
1
ingly, H and 13NMR showed only two sets of signals,
one set for S,S and R,R and the other set for S,R and
R,S. For all compounds a sufficient separation of the
resonances of the two diastereomers is found, which
allows for an easy and reliable determination of the
diastereomeric ratio.
O(4)-C(14)-C(13) 124.46(15) O(1)-C(9)-N(1)
C(9)-N(1)-C(16)
The spectra of the complexes 4k and 7 show the
familiar pattern of a [2.2.2] bicyclic complex, which has
also been observed for analogous compounds reported
earlier.6 The spectra of compounds 5 and 8 very closely
resemble those of the corresponding complexes 4.
Figure 9 shows a part of the 1H NMR spectrum of
the crude reaction mixture of the reaction of 6b and
DMAD leading to 7bk s and 7′bk s. The appearance of
the crude spectrum in Figure 9 shows not only that the
formation of 7 and 7′ is a very clean reaction but also
that the two diastereomers, unprimed and primed
assignments in Figure 9, show appreciable shift differ-
ences. This allows for an easy and reliable determina-
crystallization only one was present. However, it was
not possible to distinguish which diastereomer (SR or
RS) was present in the single-crystal X-ray determina-
(15) Leibfritz, D.; tom Dieck, H. J . Organomet. Chem. 1976, 105,
255.

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Ta ble 11. 1H NMR Da ta of Com p lexes 1 a n d 6 (Atom ic Nu m ber in g a s in Sch em e 2)
1H NMR data
Organometallics, Vol. 15, No. 8, 1996 2157
compd
1a k
9.23, 1H, d, 6.1 Hz [H(21)]; 8.08, 1H, s [H(2)]; 7.62, 1H, d, 8.1 Hz [H(18)]; 7.31, 1H, t, 7.4 Hz and 6.83, 1H, t, 6.5 Hz [H(19, 20)];
4.17, 1H, m [H(4)]; 1.57, 3H, d, 6.5 Hz [R′′]; 1.95-0.85, 11H, m [R]
1a l
9.35, 1H, d, 5.3 Hz [H(21)]; 8.73-6.83, 8H , m [R′ and H(18-20)]; 3.94-3.85, 1H, m [H(4)]; 1.78-0.79, 11H, m [R]; 1.55, d, 3H,
6.5 Hz [R′′]
1a m
1bk
8.56, 1H, d, 5.0 Hz [H(21)]; 8.12, 1H, d, 8.0 Hz [H(18)]; 7.69-7.26, 2H, m [H(19, 20)]; 3.51, 1H, m [H(4)]; 2.33, 3H, s [R′];
1.74-0.72, 11H, m [R]; 1.12, 3H, d, 6.0 Hz [R′′]
9.22, 1H, d, 6.2 Hz [H(21)]; 8.10, 1H, s [H(2)]; 7.60-6.77, 8H, m [R and H(18-20)]; 5.94, 1H, q, 6.9 Hz [H(4)]; 1.99, 3H, d,
6.9 Hz [R′′]
1bl
9.31, 1H, d, 6.2 Hz [H(21)]; 7.50-6.84, 13H, m [H(18-20); R and R′]; 5.55, 1H, q, 6.7 Hz [H(4)]; 1.97, 3H, d, 6.7 Hz [R′′]
1bm
9.32, 1H, d, 6.0 Hz [H(21)]; 8.22, 1H, d, 7.7 Hz [H(18)]; 7.75-6.89, 7H, m [H(19, 20) and R]; 6.01, 1H, q, 6.8 Hz [H(4)]; 2.30, 3H,
s [R′]; 2.05, 3H, d, 6.9 Hz [R′′]
1ck
1cl
9.23, 1H, d, 6.1 Hz [H(21)]; 8.12, 1H, s [H(2)]; 7.63, 1H, d, 8.2 Hz [H(18)]; 7.31, 1H, t, 7.9 Hz and 6.84, 1H, t, 6.6 Hz [H(19, 20)];
4.50-4.40, 1H, m [H(4)]; 2.20-1.80, 2H, m and 0.95, 3H, t, 7.3 Hz [R]; 1.59, 3H, d, 6.7 Hz [R′′]
9.35, 1H, d, 6.0 Hz [H(21)]; 7.02, 1H, d, 8.3 Hz [H(18)]; 7.52-7.18, 6H, m and 6.88, 1H, t, 6.8 Hz [R′ and H(19, 20)]; 4.25-4.13,
1H, m [H(4)]; 2.13-1.73, 2H, m and 0.74, 3H, t, 7.4 Hz [R]; 1.54, 3H, d, 6.5 Hz [R′′]
1cm
1d k
7.72, 1H, d, 6.0 Hz [H(18)]; 7.42-6.91, 2H, m [H(19, 20)]; 9.36, 1H, d, 5.1 Hz [H(21)]; 4.50, 1H, m [H(4)]; 2.09-1.98, 2H, m and
0.94, 3H, d, 6.1 Hz [R]; 2.44, 3H, s [R′]; 1.64, 3H, d, 6.3 Hz [R′′]
9.25, 1H, d, 5.6 Hz [H(21)]; 7.97, 1H, s [H(2)]; 7.68, 1H, d, 6.1 Hz [H(18)]; 7.35-6.77, 2H, m [H(19, 20)]; 4.19, 2H, ddd [H(4, 5)];
2.30-2.15, 3H, m and 1.01, 3H, t, 7.4 Hz and 0.91, 3H, d, 6.7 Hz [R]
1d l
9.32, 1H, d, 5.0 Hz [H(21)]; 7.50-6.84, 8H, m [H(18-20) and R′]; 4.30-4.05, 2H, m [H(4, 5)]; 2.25-0.70, 9H, m [R]
1d m
9.32, 1H, d, 5.9 Hz [H(21)]; 7.68, 1H, d, 8.3 Hz [H(18)]; 7.37, 1H, t, 7.8 Hz and 6.87, 1H, t, 6.5 Hz [H(19, 20)]; 4.40, 1H, dd,
12.0/6.7 Hz and 4.25, 1H, dd, 12.0/7.0 Hz [H(4, 5)]; 2.40, 3H, s [R′]; 2.34-1.25, 9H, m [R]
6a k
7.56, 2H, s [H(1, 2)]; 4.17-4.07, 2H, m [H(4)]; 2.00-0.89, 22H, m[R]; 1.51, 6H, d, 6.7 Hz [H(5)]
6a m
7.39, 1H, s [H(2)]; 4.12, 1H, m and 3.88, 1H, m [2xH(4)]; 2.10, 3H, s [R′]; 2.05-1.02, 22H, m [R]; 1.52, 3H, d, 6.5 Hz and 1.51,
3H, d, 6.6 Hz [R′′]
6bk
7.59, 2H, s [H(1, 2)]; 7.40-7.05, 10H, m [R]; 5.79, 2H, quart, 6.9 Hz [H(4)]; 1.89, 6H, d, 6.9 Hz [H(5)]
6bm
7.45-7.20, 10H, m [R]; 7.41, 1H, s [H(2)]; 5.77, 1H, q, 6.8 Hz and 5.63, 1H, q, 6.8 Hz [2xH(4)]; 1.99, 3H, d, 7.1 Hz and 1.78, 3H,
d, 7.0 Hz [R′′]; 1.98, 3H, s [R′]
a
Chemical shifts are in ppm relative to Me4Si and measured in CD2Cl2 at 263 K and 300.13 MHz.
Ta ble 12. 13C NMR Da ta of Com p lexes 1 a n d 6 (Atom ic Nu m ber in g a s in Sch em e 2)a
compd
13C NMR data
1a k
218.5 [C(8, 11, 12)]; 154.2 [C(2)]; 151.6 [C(1)]; 145.4, 129.2, 126.2, 118.2 [C(18-21)]; 75.5 [C(4)]; 22.6 [C(5, 7)]; 31.3, 30.5,
27.1, 46.3 [R]
1a l
218.9 [C(8, 11, 12)]; 156.9 [C(2)]; 154.8 [C(21)]; 152.6 [C(1)]; 130.4-128.8 [C(19) and R′]; 127.9 [C(18)]; 118.5 [C(20)]; 69.4
[C(4)]; 48.0, 31.9-26.9 [R]; 23.9 [R′′]
1a m
1bk
1bl
119.0 [C(8, 11, 12)]; 164.0 [C(2)]; 159.2 [C(1)]; 148.8 [C(21)]; 136.7 [C(19)]; 124.5 [C(18)]; 118.9 [C(20)]; 61.9 [C(4)]; 45.5,
31.6-27.2 [R]; 18.9 and 13.9 [R′ and R′′]
217.4 [C(8, 11, 12)]; 154.1 [C(2)]; 151.3 [C(1)]; 145.1, 129.3-126.4, 117.9 [[C(18-21)]; 143.9, 129.3-126.4 [R]; 71.4 [C(4);
24.6 [R′ and R′′]
217.4 [C(8, 11, 12)]; 156.6 [C(2)]; 154.8 [C(21)]; 151.9 [C(1)]; 146.1, 136.4, 129.6-127.3 [C(18, 19) and R and R′]; 118.2
[C(20)]; 65.3 [C(4)]; 25.2 [R′′]
1bm
218.0 [C(8, 11, 12)]; 154.8 [C(2)]; 154.3 [C(21)]; 151.9 [C(1)]; 144.8, 129.4-127.4 [C(18, 19) and R]; 119.5 [C(20)]; 66.6 [C(4)];
17.4 [R′]; 23.2 [R′′]
1ck
1cl
218.8 [C(8, 11, 12)]; 154.0 [C(2)]; 151.8 [C(1)]; 145.4, 129.2, 126.3, 118.4 [C(18-21)]; 71.7 [C(4)]; 33.3, 11.7 [R]; 24.8 [R′ and R′′]
219.0 [C(8, 11, 12)]; 157.0 [C(2)]; 154.7 [C(21)]; 152.6 [C(1)]; 137.1, 129.9-129.5 [C(19) and R′]; 127.9 [C(18)]; 118.6 [C(20)];
65.9 [C(4)]; 34.7, 12.2 [R]; 26.1 [R′′]
1cm
219.9 [C(8, 11, 12)]; 164.4 [C(2)]; 159.1 [C(1)]; 148.9 [C(21)]; 136.7 [C(19)]; 126.0 [C(18)]; 121.5 [C(20)]; 58.4 [C(4)]; 31.9,
12.3 [R]; 21.6 and 14.0 [R′ and R′]
1d k
1d l
218.1 [C(8, 11, 12)]; 154.6 [C(2)]; 151.2 [C(1)]; 148.1, 129.3, 125.9, 117.8 [C(18-21)]; 73.4 [C(4)]; 40.5, 27.9, 17.5, 11.9 [R]
218.5 [C(8, 11, 12)]; 157.4 [C(2)]; 154.6 [C(21)]; 152.2 [C(1)]; 130.7-127.4 [C(18, 19) and R′]; 118.3 [C(20)]; 67.3 [C(4)]; 41.8,
27.9, 17.5, 12.0 [R]
1d m
219.4 [C(8, 11, 12)]; 155.0 [C(21)]; 154.4 [C(2)]; 151.7 [C(1)]; 129.7 [C(19)]; 125.7 [C(18)]; 118.8 [C(20)]; 66.7 [C(4)]; 41.3, 28.2,
17.5, 15.9, 12.3 [R and R′]
6a k
6a m
6bk
6bm
216.8 [C(8, 11, 12)]; 143.2 [C(1, 2)]; 74.7 [C(4)]; 46.3, 31.3, 30.8, 27.2, 27.1 [R]; 22.8 [C(5)]
217.3 [C(8, 11, 12)]; 153.8 [C(1)]; 145.7 [C(2)]; 74.6 [2xC(4)]; 31.7-26.8 [R]; 23.3 and 22.8 and 17.9 [R′ and R′′]
215.3 [C(8, 11, 12)]; 143.5 [C(1, 2)]; 129.1, 128.0, 127.7 [R]; 71.0 [C(4)]; 24.6 [C(5)]
216.2 [C(8, 11, 12)]; 154.9 [C(1)]; 146.4 [C(2)]; 145.5, 144.9, 129.3-127.5 [R]; 71.4 and 65.4 [2xC(4)]; 24.6 and 23.8 and 17.8
[R′ and R′′]
a
Chemical shifts are in ppm relative to Me4Si and measured in CD2Cl2 at 263 K and 75.47 MHz.

2158 Organometallics, Vol. 15, No. 8, 1996
Ta ble 13. 1H NMR Da ta of Com p ou n d s 4, 5, 7, a n d 8
1H NMR data
Feiken et al.
compd
4a k s
major
8.56, 1H, d, 5.2 Hz [H(21)]; 7.81, 1H, t, 7.5 Hz [H(19)]; 7.53, 1H, d, 7.5 Hz [H(18)]; 7.18, 1H, t, 6.8 Hz [H(20)]; 5.95, 1H,
s [H(2)]; 4.42-4.35, 1H, m [H(4)]; 3.82, 3.73, 2 × 3H, 2 s [H(14, 16)]; 1.80-0.55, 11H, m [R]; 1.16, 3H, d, 6.8 Hz [R′′]
8.56, 1H, d, 5.2 Hz [H(21)]; 7.81, 1H, t, 7.5 Hz [H(19)]; 7.53, 1H, d, 7.5 Hz [H(18)]; 7.18, 1H, t, 6.8 Hz [H(20)]; 5.97, 1H,
minor
s [H(2)]; 4.42-4.35, 1H, m [H(4)]; 3.83, 3.75, 2 × 3H, 2 s [H(14, 16)]; 1.80-0.55, 11H, m [R]; 1.04, 3H, d, 6.8 Hz [R′′]
4bk s
major
8.45, 1H, d, 5.5 Hz [H(21)]; 7.44-6.34, 8H, m [R and H(18-20)]; 5.96, 1H, q, 6.9 Hz [H(4)]; 5.70, 1H, s [H(2)]; 3.83, 3.74,
2 × 3H, 2 s [H(14, 16)]; 1.55, 3H, d, 7.0 Hz [R′′]
minor
8.55, 1H, d, 5.5 Hz [H(21)]; 7.44-6.34, 8H, m [R and H(18-20)]; 6.03, 1H, q, 7.0 Hz [H(4)]; 5.56, 1H, s [H(2)]; 3.81, 3.34,
2 × 3H, 2 s [H(14, 16)]; 1.42, 3H, d, 7.1 Hz [R′′]
4ck s
major
8.55, 1H, d, 5.5 Hz [H(21)]; 7.85-7.79, 1H, m [H(19)]; 7.53, 1H, d, 7.5 Hz [H(18)]; 7.73-7.13, 1H, m [H(20)]; 5.97, 1H,
s [H(2)]; 4.66-4.52, 1H, m [H(4)]; 3.82, 3.74, 2 × 3H, 2 s [H(14, 16)]; 1.90-1.40, 2H, m and 0.50, 3H, t, 3.7 Hz [R];
1.15, 3H, d, 6.8 Hz [R′′]
minor
8.55, 1H, d, 5.5 Hz [H(21)]; 7.85-7.79, 1H, m [H(19)]; 7.53, 1H, d, 7.5 Hz [H(18)]; 7.73-7.13, 1H, m [H(20)]; 5.97, 1H,
s [H(2)]; 4.66-4.52, 1H, m [H(4)]; 3.82, 3.74, 2 × 3H, 2 s [H(14, 16)]; 1.90-1.40, 2H, m and 0.80, 3H, t, 3.7 Hz [R];
1.06, 3H, d, 6.8 Hz [R′′]
4ck sb
major
8.59, 1H, d, 5.5 Hz [H(21)]; 7.76-7.70, 1H, m [H(19)]; 7.44, 1H, d [H(18)]; 7.09-7.00, 1H, m [H(20)]; 5.88, 1H, s [H(2)];
4.59-4.47, 1H, m [H(4)]; 3.68, 3.66, 2 × 3H, 2 s [H(14, 16)]; 3.41, 9H, d, 10.7 Hz [P(OCH3)3]; 1.45-1.12, 2H, m and
0.37, 3H, t, 7.3 Hz [R]; 1.01, 3H, d, 6.8 Hz [R′′]
minor
8.59, 1H, d, 5.5 Hz [H(21)]; 7.76-7.70, 1H, m [H(19)]; 7.44, 1H, d [H(18)]; 7.09-7.00, 1H, m [H(20)]; 5.88, 1H, s [H(2)];
4.59-4.47, 1H, m [H(4)]; 3.68, 3.67, 2 × 3H , 2 s [H(14, 16)]; 3.41, 9H, d, 10.7 Hz [P(OCH3)3]; 1.45-1.12, 2H, m and
0.71, 3H, t, 7.3 Hz [R]; 0.92, 3H, d, 6.8 Hz [R′′]
4d k s
major
8.55, 1H, d, 5.5 Hz [H(21)]; 7.82, 1H, t, 7.6 Hz [H(19)]; 7.54, 1H, d, 7.6 Hz [H(18)]; 7.21, 1H, t, 6.1 Hz [H(20)]; 5.86, 1H,
s [H(2)]; 3.83, 3.74, 2 × 3H, 2 s [H(14, 16)]; 3.42-3.24, 2H, m [H(4, 5)]; 1.80-0.64, 9H, m [R]
8.55, 1H, d, 5.5 Hz [H(21)]; 7.82, 1H, t, 7.6 Hz [H(19)]; 7.54, 1H, d, 7.6 Hz [H(18)]; 7.21, 1H, t, 6.1 Hz [H(20)]; 5.87, 1H,
minor
s [H(2)]; 3.83, 3.74, 2 × 3H, 2 s [H(14, 16)]; 3.42-3.24, 2H, m [H(4, 5)]; 1.80-0.64, 9H, m [R]
4ik s
major
8.40, 1H, d, 4.2 Hz [H(21)]; 7.84-6.93, 8H, m [H(18-20) and Ph (L)]; 6.02, 1H, s [H(2)]; 5.09, 1H, q, 7.3 Hz [HC* of L];
5.89, 1H, sept, 6.9 Hz [H(4)]; 3.78, 3.73, 2 × 3H, 2 s [H(14, 16)]; 1.76, 3H, d, 6.9 Hz [Me (L)]; 1.10, 3H, d, 6.3 Hz and
1.02, 3H, d, 6.6 Hz [R and R′′]
minor
8.40, 1H, d, 4.2 Hz [H(21)]; 7.84-6.93, 8H, m [H(18-20) and Ph (L)]; 6.02, 1H, s [H(2)]; 5.04, 1H, q, 6.8 Hz [HC* of L];
5.89, 1H, sept, 6.9 Hz [H(4)]; 3.78, 3.73, 2 × 3H, 2 s [H(14, 16)]; 1.76, 3H, d, 6.9 Hz [Me (L)]; 1.10, 3H, d, 6.3 Hz and
1.02, 3H, d, 6.6 Hz [R and R′′]
5a k r
major
8.40, 1H, d, 5.3 Hz [H(21)]; 7.75-7.13, 3H, m [H(18-20)]; 5.03, 1H, s [H(2)]; 4.20, 1H, s [E′]; 3.88, 3H, s [H(14)]; 2.90-2.70,
1H, m [H(4)]; 1.80-0.78, 11H, m [R]; 0.60, 3H, d, 6.9 Hz [H(5)]
minor
8.40, 1H, d, 5.3 Hz [H(21)]; 7.75-7.13, 3H, m [H(18-20)]; 5.06, 1H, s [H(2)]; 4.20, 1H, s [E′]; 3.70, 3H, s [H(14)]; 3.31-3.10,
1H, m [H(4)]; 1.80-0.78, 11H, m [R]; 0.50, 3H, d, 6.9 Hz [H(5)]
5a k s
major
8.40, 1H, d, 5.3 Hz [H(21)]; 7.75-7.15, 3H, m [H(18-20)]; 5.09, 1H , s [H(2)]; 3.82, 3.71, 2 × 3H, 2 s [H(14, 16)]; 2.64-2.54,
1H, m [H(4)]; 1.65-0.64, 11H, m [R]; 0.48, 3H, d, 6.8 Hz [H(5)]
minor
8.40, 1H, d, 5.3 Hz [H(21)]; 7.75-7.15, 3H, m [H(18-20)]; 5.18, 1H , s [H(2)]; 3.82, 3.71, 2 × 3H, 2 s [H(14, 16)]; 2.64-2.54,
1H, m [H(4)]; 1.65-0.64, 11H, m [R]; 0.48, 3H, d, 6.8 Hz [H(5)]
5a ls
major
8.59, 1H, m/d, 4.8 Hz [H(21)]; 7.79-7.26, 8H, m [R′ and H(18-20)]; 3.81, 3.18, 2 × 3H, 2 s [H(14, 16)]; 2.28-2.20, 1H, m
[H(4)]; 1.79 to -0.40, 11H, m [R]; 1.38, 3H, d, 6.9 Hz [R′′]
5a m r
major
8.44, 1H, d, 5.4 Hz [H(21)]; 7.71, 1H, t, 7.5 Hz [H(19)]; 7.25, 1H, d, 7.8 Hz [H(18)]; 7.13, 1H, t, 7.8 Hz [H(20)]; 4.19, 1H,
s [E′]; 3.64, 3H, s [H(14)]; 2.16-0.85, 11H, m [R and H(4)]; 1.95, 3H, s [R′]; 1.64, 3H, d, 6.1 Hz [R′′]; -1.73, 1H, dq, 3.6
Hz/12.3 Hz [R]
minor
8.44, 1H, d, 5.4 Hz [H(21)]; 7.71, 1H, t, 7.5 Hz [H(19)]; 7.25, 1H, d, 7.8 Hz [H(18)]; 7.13, 1H, t, 7.8 Hz [H(20)]; 4.43, 1H,
s [E′]; 3.73, 3H, s [H(14)]; 2.16-0.85, 11H, m [R and H(4)]; 1.95, 3H, s [R′]; 1.64, 3H, d, 6.1 Hz [R′′]; -1.73, 1H, dq, 3.6
Hz/12.3 Hz [R]
5a m s
major
8.41, 1H, d, 5.4 Hz [H(21)]; 7.75, 1H, t, 7.8 Hz [H(19)]; 7.27-7.15, 2H, m [H(18, 20)]; 3.81, 3.63, 2 × 3H, 2 s [H(14, 16)];
1.40, 3H, s [R′]; 2.15 to -0.07, 10H, m [R]; 1.31, 3H, d, 6.6 Hz [R′′]; -1.67, 1H, dq, 3.3 Hz/12.3 Hz [R]
minor
8.41, 1H, d, 5.4 Hz [H(21)]; 7.75, 1H, t, 7.8 Hz [H(19)]; 7.27-7.15, 2H, m [H(18, 20)]; 3.81, 3.63, 2 × 3H, 2 s [H(14, 16)];
2.01, 3H, s [R′]; 2.15 to -0.07, 10H, m [R]; 0.94, 3H, d, 6.6 Hz [R′′]; -1.67, 1H, dq, 3.3 Hz/12.3 Hz [R]
5bk r
major
8.13, 1H, d, 5.3 Hz [H(21)]; 7.55-6.67, 8H, m [R and H(18-20)]; 5.37, 1H, q, 7.2 Hz [H(4)]; 5.28, 1H, s [H(2)]; 4.29, 1H,
s [E′]; 3.66, 3H, s [H(14)]; 1.63, 3H, d, 7.2 Hz [R′′]
minor
8.34, 1H, d, 5.4 Hz [H(21)]; 7.55-6.67, 8H, m [R and H(18-20)]; 5.12, 1H, q, 7.0 Hz [H(4)]; 4.91, 1H, s [H(2)]; 4.32, 1H,
s [E′]; 3.66, 3H, s [H(14)]; 1.63, 3H, d, 7.2 Hz [R′′]

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2159
Ta ble 13 (Con tin u ed )
compd
1H NMR data
5bk s
major
8.13, 1H, d, 4.8 Hz [H(21)]; 7.50-6.68, 8H, m [H(18-20) and R]; 5.38, 1H, s [H(2)]; 5.29, 1H, q, 7.2 Hz [H(4)]; 3.87, 3.71,
2 × 3H, 2 s [H(14, 16)]; 1.63, d, 3H, 7.2 Hz [R′′]
minor
8.31, 1H, d, 5.1 Hz [H(21)]; 7.50-6.68, 8H, m [H(18-20) and R]; 5.03, 1H , s [H(2)]; 5.01, 1H, q, 7.0 Hz [H(4)]; 3.87, 3.71,
2 × 3H, 2 s [H(14, 16)]; 0.76, 3H, d, 7.1 Hz [R′′]
5blr
major
8.28, 1H, d, 5.6 Hz [H(21)]; 7.90-6.51, 13H, m [R; R′ and H(18-20)]; 4.40, 1H, s [E′]; 3.84, 1H, q, 6.5 Hz [H(4)]; 3.30, 3H,
s [H(14)]; 1.89, 3H, d, 7.2 Hz [R′′]
minor
8.55, 1H, d, 5.2 Hz [H(21)]; 7.90-6.51, 13H, m [R; R′ and H(18-20)]; 4.40, 1H, s [E′]; 5.20, 1H, q, 6.6 Hz [H(4)]; 3.24, 3H,
s [H(14)]; 0.55, 3H, d, 7.1 Hz [R′′]
5bls
major
8.25, 1H, d, 5.4 Hz [H(21)]; 7.81-6.54, 14H, m [R; R′ and H(4, 18-20)]; 3.88, 3.23, 2 × 3H, 2 s [H(14, 16)]; 1.86, 3H, d,
7.2 Hz [R′′]
minor
8.60, 1H, d, 5.4 Hz [H(21)]; 7.81-6.54, 14H, m [R; R′ and H(4, 18-20)]; 3.84, 3.12, 2 × 3H, 2 s [H(14, 16)]; 0.45, 3H, d,
7.2 Hz [R′′]
5bm r
major
8.10, 1H, d, 5.6 Hz [H(21)]; 7.80-6.60, 8H, m [R and H(18-20)]; 4.37, 1H, s [E′]; 3.99, 1H, q, 7.3 Hz [H(4)]; 3.66, 3H, s
[H(14)]; 2.04, 3H, s [R′]; 1.76, 3H, d, 7.3 Hz [R′′]
minor
8.48, 1H, d, 5.4 Hz [H(21)]; 7.77-6.60, 8H, m [R and H(18-20)]; 4.36, 1H, s [E′]; 3.82, 1H, q, 7.1 Hz [H(4)]; 3.65, 3H, s
[H(14)]; 1.95, 1H, s [R′]; 0.74, 3H, d, 7.0 Hz [R′′]
5bm s
major
8.03, 1H, d, 5.3 Hz [H(21)]; 7.83-6.64, 8H, m [R and H(18-20)]; 3.87, 3.66, 2 × 3H, 2 s [H(14, 16)]; 3.97, 1H, q, 6.4 Hz
[H(4)]; 2.11, 3H, s [R′]; 1.74, 3H, d, 7.2 Hz [R′′]
minor
8.46, 1H, d, 5.3 Hz [H(21)]; 7.83-6.64, 8H, m [R and H(18-20)]; 3.86, 3.66, 2 × 3H , 2 s [H(14, 16)]; 3.80, 1H, q, 6.6 Hz
[H(4)]; 1.98, 3H, s [R′]; 0.71, 3H, d, 7.0 Hz [R′′]
5ck r
major
8.40, 1H, d, 5.5 Hz [H(21)]; 7.67, 1H, t, 7.6 Hz [H(19)]; 7.38, 1H, d, 7.7 Hz [H(18)]; 7.17, 1H, t, 5.9 Hz [H(20)]; 5.10, 1H,
s [H(2)]; 4.22, 1H , s [E′]; 3.68, 3H , s [H(14)]; 3.28-3.14, 1H, m [H(4)]; 1.46-0.97, 2H, m and 0.64, 3H, t, 7.1 Hz [R];
0.71, 3H, d, 6.4 Hz [R′′]
minor
8.40, 1H, d, 5.5 Hz [H(21)]; 7.67, 1H, t, 7.6 Hz [H(19)]; 7.38, 1H, d, 7.7 Hz [H(18)]; 7.17, 1H, t, 5.9 Hz [H(20)]; 5.11, 1H,
s [H(2)]; 4.21, 1H, s [E′]; 3.67, 3H, s [H(14)]; 3.43-3.31, 1H , m [H(4)]; 1.46-0.97, 2H, m and 0.47, 3H, t, 7.4 Hz [R];
0.60, 3H, d, 6.6 Hz [R′′]
5ck s
major
8.37, 1H, d, 5.5 Hz [H(21)]; 7.77-7.69, 1H, m [H(19)]; 7.40, 1H, d, 7.6 Hz [H(18)]; 7.25-7.19, 1H, m [H(20)]; 5.14, 1H , s
[H(2)]; 3.77, 3.66, 2 × 3H , 2 s [H(14, 16)]; 3.08-2.96, 1H, m [H(4)]; 1.50-0.91, 2H, m and 0.67, 3H, t, 7.3 Hz [R];
0.53, 3H, d, 6.8 Hz [R′′]
minor
8.37, 1H, d, 5.5 Hz [H(21)]; 7.77-7.69, 1H, m [H(19)]; 7.40, 1H, d, 7.6 Hz [H(18)]; 7.25-7.19, 1H, m [H(20)]; 5.18, 1H, s
[H(2)]; 3.77, 3.66, 2 × 3H , 2 s [H(14, 16)]; 3.29-3.17, 1H, m [H(4)]; 1.50-0.91, 2H, m and 0.43, 3H, t, 7.3 Hz [R];
0.57, 3H, d, 6.8 Hz [R′′]
5clr
major
8.59, 1H, d, 4.5 Hz [H(21)]; 7.74-7.19, 8H, m [R and H(18-20)]; 4.29, 1H , s [E′]; 3.25, 3H, s [H(14)]; 2.26, 1H , m [H(4)];
1.42, 3H, d, 6.9 Hz [R′′]; 0.25, 3H, t, 7.5 Hz and 1.85, 1H, m and -1.23, 1H, m [R]
minor
8.59, 1H, d, 4.5 Hz [H(21)]; 7.74-7.19, 8H, m [R and H(18-20)]; 4.30, 1H, s [E′]; 3.25, 3H, s [H(14)]; 2.26, 1H , m [H(4)];
0.64, 3H , t, 7.5 Hz and 1.85, 1H, m and -1.23, 1H , m [R]; -0.05, 3H, d, 6.0 Hz [R′′]
5cls
major
8.56, 1H, d, 5.1 Hz [H(21)]; 7.99-7.01, 8H, m [R′ and H(18-20)]; 3.80, 3.15, 2 × 3H , 2 s [H(14, 16)]; 2.24, 1H, m [H(4)];
1.41, 3H, d, 6.6 Hz [R′′]; 0.24, 3H, t, 7.5 Hz and -1.41, 2H , m [R]
minor
7.97, 1H, d, 5.1 Hz [H(21)]; 7.99-7.01, 8H, m [R′ and H(18-20)]; 3.77, 3.22, 2 × 3H, 2 s [H(14, 16)]; 2.24, 1H, m [H(4)];
-0.28, 3H, d, 6.0 Hz [R′′]; 0.66, 3H, t, 6.9 Hz and -1.41, 2H, m [R]
5cm r
major
8.43, 1H, d, 5.4 Hz [H(21)]; 7.74-7.11, 3H, m [H(18-20)]; 4.24, 1H, s [E′]; 3.64, 3H, s [H(14)]; 2.44, 1H, m, 6.9 Hz [H(4)];
1.93, 3H, s [R′]; 1.43, 0.55, 2 × 1H, m and -0.10, 3H, t, 7.5 Hz [R]; 1.32, 3H, d, 6.9 Hz [R′′];
minor
8.43, 1H, d, 5.4 Hz [H(21)]; 7.74-7.11, 3H, m [H(18-20)]; 4.31, 1H, s [E′]; 3.64, 3H, s [H(14)]; 2.44, 1H, m, 6.9 Hz [H(4)];
1.90, 3H , s [R′]; 1.43, 0.55, 2 × 1H, m and 0.85, 3H, t, 7.5 Hz [R]; 0.05, d, 3H, 6.8 Hz [R′′]
5cm s
major
8.41, 1H, d, 5.7 Hz [H(21)]; 7.77-7.13, 3H, m [H(18-20)]; 3.84, 3.65, 2 × 3H, 2 s [H(14, 16)]; 2.42, 1H, m [H(4)]; 2.01, 3H,
s [R′]; 1.54, 2H , m and 0.87, 3H, t, 7.5 Hz [R]; 1.32, 3H, d, 6.9 Hz [R′′]
minor
8.41, 1H, d, 5.7 Hz [H(21)]; 7.77-7.13, 3H, m [H(18-20)]; 3.84, 3.65, 2 × 3H, 2 s [H(14, 16)]; 2.42, 1H, m [H(4)]; 1.98, 3H,
s [R′]; 0.15, 2H , m and 0.00, 3H, t, 5.7 Hz [R]; 0.03, 3H, d, 6.6 Hz [R′′]
5d lr
major
8.50, 1H, d, 5.7 Hz [H(21)]; 8.08-7.13, 8H, m [R′ and H(18-20)]; 4.31, 1H, s [E′]; 3.29, 3H, s [H(14)]; 2.81-2.22, 2H, 8 d,
8 × 7.3 Hz [H(4, 5)]; 1.30-0.55, 6H , m and 0.27, 3H, d, 6.6 Hz [R]
minor
8.50, 1H, d, 5.7 Hz [H(21)]; 8.08-7.13, 8H, m [R′ and H(18-20)]; 4.33, 1H, s [E′]; 3.28, 3H, s [H(14)]; 2.81-2.22, 2H, 8 d,
8 × 7.3 Hz [H(4, 5)]; 1.30-0.55, 6H , m and 0.41, 3H, d, 6.6 Hz [R]

2160 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
Ta ble 13 (Con tin u ed )
compd
1H NMR data
5d ls
major
8.54, 1H, d, 5.5 Hz [H(21)]; 7.79-7.17, 8H, m [R′ and H(18-20)]; 3.87, 3.18, 2 × 3H, 2 s [H(14, 16)]; 2.30-2.01, 2H, m
[H(4, 5)]; 1.68-0.56, 9H, m [R]
minor
8.54, 1H, d, 5.5 Hz [H(21)];.7.79-7.17, 8H, m [R′ and H(18-20)]; 3.86, 3.17, 2 × 3H, 2 s [H(14, 16)]; 2.30-2.01, 2H , m
[H(4, 5)]; 1.68-0.56, 9H, m [R]
5d m r
major
8.39, 1H, d, 5.3 Hz [H(21)]; 7.73, 1H, t, 7.5 Hz [H(19)]; 7.23, 1H, d, 6.9 Hz [H(18)]; 7.12, 1H, t, 6.4 Hz [H(20)]; 4.40, 1H,
s [E′]; 3.65, 3H, s [H(14)]; 2.59-1.87, 2H, m [H(4, 5)]; 1.95, 3H, s [R′]; 1.68-1.15, 3H, m and 0.78, 3H, t, 6.9 Hz and
0.70, 3H, d, 5.8 Hz [R]
minor
8.39, 1H, d, 5.3 Hz [H(21)]; 7.73, 1H, t, 7.5 Hz [H(19)]; 7.23, 1H, d, 6.9 Hz [H(18)]; 7.12, 1H, t, 6.4 Hz [H(20)]; 4.40, 1H,
s [E′]; 3.65, 3H, s [H(14)]; 2.59-1.87, 2H, m [H(4, 5)]; 1.95, 3H, s [R′]; 1.68-0.85, 3H, m and 0.78, 3H, t, 6.9 Hz and
0.70, 3H, d, 5.8 Hz [R]
5d m s
major
8.54, 1H, d, 5.9 Hz [H(21)]; 7.76, 1H, t, 7.6 Hz [H(19)]; 7.29-7.10, 2H, m [H(18, 20)]; 3.85, 3.66, 2 × 3H, 2 s [H(14, 16)];
2.01, 3H, s [R′]; 2.90-1.20, 10H, m [R and H(4)]
minor
8.53, 1H, t, 5.9 Hz [H(21)]; 7.92, 1H, t, 5.9 Hz [H(19)]; 7.54, 1H, d, 8.3 Hz [H(18)]; 7.29-7.10, 1H, m [H(20)]; 3.79, 3.32,
2 × 3H, 2 s[H(14, 16)]; 2.00, 3H, s [R′]; 2.90-1.20, 10H, m [R and H(4)]
5d k r
major
8.39, 1H, d, 5.1 Hz [H(21)]; 7.71, 1H, t, 7.3 Hz [H(19)]; 7.21, 1H , d [H(18)]; 7.11, 1H, t, 6.0 Hz [H(20)]; 5.14, 1H, s [H(2)];
4.30, 1H , s [E′]; 3.72, 3H , s [H(14)]; 3.30-3.11, 2H, m [H(4, 5)]; 1.85-0.60, 9H , m [R]
5d k s
major
8.36, 1H, d, 5.3 Hz [H(21)]; 7.74, 1H, t, 7.5 Hz [H(19)]; 7.27-7.10, 2H, m, [H(18, 20)]; 5.21, 1H , s [H(2)]; 3.80, 3.73, 2 × 3H,
2 s [H(14, 16)]; 3.21-3.00, 2H, m [H(4, 5)]; 1.74-0.82, 9H, m [R]
minor
8.36, d, 1H, 5.3 Hz [H(21)]; 7.74, t, 1H, 7.5 Hz [H(19)]; 7.27-7.10, 2H, m, [H(18, 20)]; 5.22, 1H, s [H(2)]; 3.80, 3.73, 2 × 3H,
2 s [H(14, 16)]; 3.21-3.00, 2H, m [H(4, 5)]; 1.74-0.82, 9H, m [R]
7a k s
major
8.36, 1H, d, 5.2 Hz [H(1)]; 5.77, 1H, d, 5.1 Hz [H(2)]; 4.31-4.21, 1H, m [H(4)]; 3.45-3.35, 1H, m [H(4)]; 3.80, 3H, s and
3.75, 3H, s [H(14, 16)]; 1.23, 3H, d, 6.6 Hz and 1.07, 3H, d, 6.8 Hz [H(5,)]; 1.80-0.82, 22H, m [R]
minor
8.36, 1H,d, 5.2 Hz [H(1)]; 5.76, 1H, d, 5.1 Hz [H(2)]; 4.31-4.21, 1H, m [H(4)]; 3.81, 3H, s and 3.74, 3H, s [H(14, 16)];
3.45-3.35, 1H, m [H(4)]; 1.23, 3H, d, 6.6 Hz and 1.07, 3H, d, 6.8 Hz [H(5)]; 1.80-0.82, 22H, m [R]
7a k sb
major
8.42, 1H, dd, 5.0/2.7 Hz [H(1)]; 5.67, 1H, d, 5.3 Hz [H(2)]; 4.34-4.24, 1H, m [H(4)]; 4.02-3.61, 1H, m [H(4)]; 3.75, 3.73, 6H,
2 s [H(14, 16)]; 3.73, 9H, d, 10.1 Hz [L′]; 1.21, 3H, d, 6.9 Hz and 1.12, 3H, d, 6.9 Hz [H(5)]; 1.80-0.85, 22H, m [R]
minor
8.35, 1H, dd, 5.1/2.8 Hz [H(1)]; 5.71, 1H, d, 5.2 Hz [H(2)]; 4.34-4.24, 1H, m [H(4)]; 4.02-3.61, 1H, m [H(4)]; 3.74, 3.66, 6H,
2 s [H(14, 16)]; 3.71, 9H, d, 10.5 Hz [L′]; 0.98, 6H, pst, 6.7 Hz [H(5)]; 1.80-0.85, 22H, m [R]
7ik s
major
8.38, 1H, d, 5.1 Hz [H(1)]; 5.78, 1H, d, 5.1 Hz [H(2)]; 4.78, 1H, sept, 6.8 Hz [H(4)]; 3.39, 1H, sept, 6.8 Hz [H(4)]; 3.74, 3H,
s and 3.71, 3H, s [H(14, 16)]; 1.22, 6H, d, 6.7 Hz and 1.05, 6H, d, 6.8 Hz and 1.01, 6H, d, 6.8 Hz and 0.97, 3H, d, 6.7 Hz
and 0.96, 3H, d, 6.7 Hz [H(5) of major and minor compd]; 1.76, 3H, d, 6.8 Hz and 5.09, 1H, quart, 6.8 Hz and 7.5-7.4,
5H, m [L]
minor
8.38, 1H, d, 5.1 Hz [H(1)]; 5.78, 1H, d, 5.1 Hz [H(2)]; 4.78, 1H, sept, 6.8 Hz [H(4)]; 3.76, 3H, s and 3.73, 3H, s [H(14, 16)];
3.39, 1H, sept, 6.8 Hz [H(4)]; 1.22, 6H, d, 6.7 Hz and 1.05, 6H, d, 6.8 Hz and 1.01, 6H, d, 6.8 Hz and 0.97, 3H, d, 6.7 Hz
and 0.96, 3H, d, 6.7 Hz [H(5) of major and minor compd]; 1.77, 3H, d, 6.8 Hz and 5.08, 1H, quart, 6.8 Hz and 7.5-7.4,
5H, m [L]
7a m s
major
5.30, 1H, s [H(2)]; 4.37-4.30, 1H, m [H(4)]; 3.79, 3.73, 2 × 3H, 2 s [H(14, 16)]; 3.57-3.51, 1H , m [H(4)]; 2.35, 3H, s [H(7)];
1.80-0.81, 44H, m [R]; 1.29, 3H, d, 6.8 Hz and 0.95, 3H, d, 6.9 Hz [H(5)]
7a m sb
major
5.31, 1H, s [H(2)]; 4.39-4.28, 1H, m [H(4)]; 3.75, 9H, d, 10.0 Hz [P(OCH3)3]; 3.81-3.67, 1H , m [H(4)]; 3.72, 3.71, 2 ¥ 3H ,
2 s [H(14, 16)]; 2.37, 3H, s [H(7)]; 1.75-0.77, 44H , m [R]; 1.27, 3H, d, 6.6 Hz and 0.93, 3H, d, 6.7 Hz [H(5)]
minor
5.39, 1H, s [H(2)]; 4.39-4.28, 1H, m [H(4)]; 3.53, 9H, d, 10.6 Hz [P(OCH3)3]; 3.81-3.67, 1H , m [H(4)]; 3.72, 3.71, 2 × 3H,
2 s [H(14, 16)]; 2.39, 3H, s, [H(7)]; 1.75-0.77, 44H, m [R]; 1.20, 3H, d, 6.6 Hz and 1.15, 3H, d, 6.7 Hz [H(5)]
7bk s
major
7.74, 1H, d, 5.1 Hz [H(1)]; 7.49-6.86, 20H, m [R]; 5.90, 1H, quart, 6.8 Hz [H(4)]; 5.57, 1H, d, 5.1 Hz [H(2)]; 4.85, 1H, quart,
6.6 Hz [H(4)]; 3.77, 3H, s and 3.76, 3H, s [H(14, 16)]; 1.43, 6H, pst, 6.7 Hz[H(5)]
minor
8.42, 1H, d, 5.1 Hz [H(1)]; 7.49-6.86, 20H, m [R]; 5.90, 1H, quart, 6.8 Hz [H(4)]; 5.39, 1H, d, 5.2 Hz [H(2)]; 4.91, 1H, quart,
6.6 Hz [H(4)]; 3.82, 3H, s and 3.35, 3H, s [H(14, 16)]; 1.57, 3H, d, 6.6 Hz and 1.52, 3H, d, 6.6 Hz [H(5)]
7bk sb
major
7.63, 1H, dd, 5.1/2.9 Hz [H(1)]; 7.40-6.97, 20H, m [R]; 5.89, 1H, quart, 6.6 Hz[H(4)]; 5.43, 1H, d, 5.2 Hz [H(2)]; 4.97, 1H,
quart, 6.7 Hz[H(4)]; 3.73, 3H, s and 3.68, 3H, s [H(14, 16)]; 3.60, 9H, d, 10.4 Hz [L′]; 1.49, 3H, d, 6.7 Hz and 1.39, 3H, d,
6.7 Hz [H(5)]
minor
8.67, 1H, dd, 5.2/3.0 Hz [H(1)]; 7.40-6.97, 20H, m [R]; 5.98, 1H, quart, 6.7 Hz[H(4)]; 5.43, 1H, d, 5.2 Hz [H(2)]; 5.07, 1H,
quart, 6.7 Hz[H(4)]; 3.72, 3H, s and 3.25, 3H, s [H(14, 16)]; 3.67, 9H, d, 10.6 Hz [L′]; 1.49, 3H, d, 6.7 Hz and 0.83, 3H,
d, 6.8 Hz [H(5)]

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2161
Ta ble 13 (Con tin u ed )
compd
1H NMR data
7bk sc
major
8.29, 1H, d, 5.2 Hz [H(1)]; 7.41-7.10, 20H, m [R]; 5.95, 1H, quart, 6.6 Hz[H(4)]; 5.30, 1H, d, 5.1 Hz [H(2)]; 5.94,1H, sept,
6.6 Hz[H(4)]; 3.81, 3H, s and 3.30, 3H, s [H(14, 16)]; 1.56, 9H, s [L]; 1.45, 3H, d, 7.1 Hz and 1.30, 3H, d, 6.7 Hz [H(5)]
minor
7.59, 1H, d, 5.0 Hz [H(1)]; 7.41-7.10, 20H, m [R]; 5.93, 1H, quart, 6.6 Hz[H(4)]; 5.94, 1H, sept, 6.6 Hz[H(4)]; 5.46, 1H, d,
5.0 Hz [H(2)]; 3.83, 3H, s and 3.73, 3H, s [H(14, 16)]; 1.50, 6H, pst, 6.9/7.1 Hz [H(5)]; 1.29, 9H, s [L]
7bm s
major
7.55-7.12, 8H, m [R]; 6.92, 6.89, 2 × 1H, s [R]; 6.00, 1H, q, 6.9 Hz [H(4)]; 5.22, 1H, s [H(2)]; 5.10, 1H, q, 7.1 Hz [H(4)];
3.87, 3.78, 2 × 3H, 2 s [H(14, 16)]; 1.57, 3H, d, 7.0 Hz [H(5)]; 1.49, 3H, d, 7.0 Hz [H(5)]; 0,98, 3H, s [R′]
minor
7.55-7.12, 8H, m [R]; 6.92, 6.89, 2 × 1H, s [R]; 6.00, 1H, q, 6.9 Hz [H(4)]; 5.02, 1H, s [H(2)]; 5.10, 1H, q, 7.1 Hz [H(4)];
3.85, 3.36, 2 × 3H, 2 s [H(14, 16)]; 1.22, 3H, d, 6.8 Hz [H(5)]; 1.19, 3H, d, 7.5 Hz [H(5)]; 0,97, 3H, s [R′]
8a ls
major
8.66, 1H, m/d, 4.8 Hz [H(21)]; 7.80-7.33, 8H, m [R′ and H(18-20)]; 3.93, 3.59, 2 × 3H, 2 s [H(14, 16)]; 3.34, 1H, sept,
5.9 Hz [H(4)]; 1.42, 3H, d, 6.9 Hz [R′′]; 1.77-0.62, 10H, m and -0.30 to -0.40, 1H, m [R]
8bm r
major
8.52, 1H, d, 3.0 Hz [H(21)]; 7.70-6.92, 8H, m [R and H(18-20)]; 6.84, 1H, s [E′]; 4.55, 1H, q, 7.2 Hz [H(4)]; 3.69, 3H, s
[H(14)]; 2.01, 3H , s [R′]; 1.74, 3H, d, 7.2 Hz [R′′]
minor
8.62, 1H, d, 3.0 Hz [H(21)]; 7.67, 1H, t, 7.6 Hz [H(19)]; 7.70-6.92, 8H, m [R and H(18, 19, 20)]; 6.84, 1H, s [E′]; 4.25,
1H, q, 7.1 Hz [H(4)]; 3.69, 3H, s [H(14)]; 1.87, 3H, s [R′]; 1.52, 3H, d, 7.1 Hz [R′′]
8bm s
major
8.56, 1H, d, 4.7 Hz [H(21)]; 8.13-6.86, 8H, m [R and H(18-20)]; 4.54, 1H, q, 7.1 Hz [H(4)]; 3.85, 3.67, 2 × 3H , 2 s
[H(14, 16)]; 2.01, 3H , s [R′]; 1.73, 3H, d, 7.0 Hz [R′′]
minor
8.64, 1H, d, 4.6 Hz [H(21)]; 8.13-6.86, 8H, m [R and H(18-20)]; 4.54, 1H, q, 7.1 Hz [H(4)]; 3.85, 3.67, 2 × 3H , 2 s
[H(14, 16)]; 1.94, 3H, s [R′]; 1.56, 3H, d, 6.8 Hz [R′′]
8ck r
major
8.58, 1H, d, 5.4 Hz [H(21)]; 7.67, 1H, t, 7.4 Hz [H(19)]; 7.35-7.20, 2H, m [H(18, 20)]; 6.93, 1H, s [E′]; 5.49, 1H, s [H(2)];
4.05, 1H, m, 7.0 Hz [H(4)]; 3.68, 3H, s [H(14)]; 1.83-1.07, 2H, m and 0.72, 3H, t, 6.7 Hz [R]; 1.24, 3H, d, 6.7 Hz [R′′]
minor
8.58, 1H, d, 5.4 Hz [H(21)]; 7.67, 1H, t, 7.4 Hz [H(19)]; 7.35-7.20, 2H, m [H(18, 20)]; 6.93, 1H , s [E′]; 5.46, 1H, s [H(2)];
3.90, 1H, m, 7.0 Hz [H(4)]; 3.68, 3H , s [H(14)]; 1.83-1.07, 2H, m and 0.75, 3H, t, 6.7 Hz [R]; 1.63, 3H, d, 7.2 Hz [R′′]
8cls
major
8.61, 1H, d, 4.6 Hz [H(21)]; 7.72, 1H, t, 7.8 Hz [H(19)]; 7.43-7.26, 7H, m [R′ and H(18, 20)]; 3.89, 3.66, 2 × 3H, 2 s
[H(14, 16)]; 3.34-0.66, 3H, m [H(4) and R]; 1.30, 3H, d, 6.8 Hz [R′′]; 0.43, 3H, t, 7.4 Hz [R]
minor
8.61, 1H, d, 4.6 Hz [H(21)]; 7.72, 1H, t, 7.8 Hz [H(19)]; 7.43-7.26, 7H, m [R′ and H(18, 20)]; 3.89, 3.66, 2 × 3H, 2 s
[H(14, 16)]; 3.34-0.66, 3H , m [H(4) and R]; 0.84, 3H, d, 6.6 Hz [R′′]; 0.61, 3H, t, 7.4 Hz [R]
8cm r
major
8.52, 1H, d, 5.2 Hz [H(21)]; 7.59, 1H, t, 7.8 Hz [H(19)]; 7.20-7.11, 2H, m [H(18, 20)]; 6.85, 1H, s [E′]; 3.66, 3H, s [H(14)];
3.08, 1H, m, 7.1 Hz [H(4)]; 1.92, 3H, s [R′]; 1.87-1.40, 2H, m and 0.25, 3H, t, 7.6 Hz [R]; 1.30, 3H, d, 6.8 Hz [R′′]
minor
8.52, 1H, d, 5.2 Hz [H(21)]; 7.59, 1H, t, 7.8 Hz [H(19)]; 7.20-7.11, 2H , m [H(18, 20)]; 6.85, 1H, s [E′]; 3.65, 3H, s [H(14)];
3.00, 1H, m, 7.1 Hz [H(4)]; 1.90, 3H, s [R′]; 1.87-1.40, 2H, m and 0.81, 3H, t, 7.5 Hz [R]; 0.81, 3H, d, 6.8 Hz [R′′]
a
“Major” and “minor” identify the values for the major and minor diastereomers of the respective compound. The resonances are
characterized in consecutive order by chemical shift (ppm), integral, multiplicity, coupling constant, and (in brackets) the assignment
b
according to Scheme 2. Chemical shifts are in ppm relative to Me4Si and measured in CDCl3 at 293 K and 300.13 MHz. With L )
P(OMe)3. c With L ) tBu-NC.
F igu r e 9. 1H NMR spectrum of the crude reaction mixture 7/7′bk s (in CDCl3 at 300.13 MHz).

2162 Organometallics, Vol. 15, No. 8, 1996
Ta ble 14. 13C NMR Da ta of Com p ou n d s 4, 5, 7, a n d 8
13C NMR data
Feiken et al.
compd
4a k s
major
206.4, 204.7, 202.4 [L and C(3, 11, 12)]; 190.8 [C(10)]; 178.2 [C(15)]; 161.7, 161.2 [C(1, 13)]; 156.0 [C(21)]; 139.8 [C(19)];
130.3 [C(9)]; 124.7 [C(18)]; 123.3 [C(20)]; 60.3 [C(2)]; 54.8 [C(4)]; 52.8, 52.0 [C(14, 16)]; 42.6, 30.4, 26.6, 26.5, 26.2 [R];
17.2 [C(5)]
4bk s
major
206.0, 202.8, 204.5, 201.4 [L and C(3, 11, 12)]; 190.5 [C(10)]; 178.0 [C(15)]; 161.2, 161.1 [C(1, 13)]; 155.3 [C(21)]; 139.2
[C(19)]; 130.0 [C(19)]; 141.6, 128.8, 128.3, 127.8 [R]; 124.7 [C(18)]; 123.0 [C(20)]; 60.5 [C(2)]; 52.8, 52.1, 51.5 [C(4, 14,
16)]; 16.8 [C(5)]
4ck s
major
205.5, 204.6, 203.7, 201.4 [L and C(3, 11, 12)]; 190.9 [C(10)]; 178.5 [C(15)]; 161.5, 161.1 [C(1, 13)]; 156.0 [C(21)]; 140.2
[C(19)]; 130.2 [C(9)]; 124.9 [C(18)]; 123.5 [C(20)]; 59.6 [C(2)]; 53.1, 52.3, 51.4 [C(4, 14, 16)]; 28.8, 11.6 [R]; 18.3 [C(5)]
minor
206.6, 204.5, 203.7, 201.3 [L and C(3, 11, 12)]; 190.7 [C(10)]; 178.5 [C(15)]; 161.6, 161.2 [C(1, 13)]; 156.0 [C(21)]; 140.2
[C(19)]; 130.0 [C(9)]; 124.9 [C(18)]; 123.5 [C(20)]; 59.6 [C(2)]; 53.1, 52.3, 51.4 [C(4, 14, 16)]; 28.8, 11.7 [R]; 19.7 [C(5)]
4ck sb
major
212-209.3, m [C(3, 11, 12)]; 197.1 [C(10)]; 179.0 [C(15)]; 162.0 161.8 [C(1, 13)]; 156.2 [C(21)]; 139.5 [C(19)]; 130.8, 7.5Hz
[C(9)]; 124.0 [C(18)]; 122.4 [C(20)]; 59.6 [C(2)]; 53.2-52.9 [P(OCH3)3]; 52.6, 2.3Hz [C(4)]; 51.8, 50.1 [C(14, 16)]; 28.7 [R];
11.5, 18.3Hz [R]; 19.4, 20.8Hz [C(5)]
minor
212-209.3, m [C(3, 11, 12)]; 197.1 [C(10)]; 179.0 [C(15)]; 162.0 161.8 [C(1, 13)]; 156.2 [C(21)]; 139.3 [C(19)]; 130.9, 7.5Hz
[C(9)]; 123.9 [C(18)]; 122.2 [C(20)]; 59.8 [C(2)]; 53.2-52.9 [P(OCH3)3]; 13.1Hz [C(4)]; 51.3, 50.2 [C(14, 16)]; 28.9 [R];
11.4, 17.3Hz [R]; 19.3, 22.3Hz [C(5)]
4d k s
major
206.5, 204.3, 203.9, 201.1 [L and C(3, 11, 12)]; 189.9 [C(10)]; 178.3 [C(15)]; 161.1, 160.4 [C(1, 13)]; 156.0 [C(21)]; 140.1
[C(19)]; 129.7 [C(9)]; 124.9 [C(18)]; 123.6 [C(20)]; 65.2 [C(2)]; 53.5 [C(4)]; 52.9, 52.2 [C(14, 16)]; 34.7, 26.9, 17.2, 11.8 [R′′]
minor
206.5, 204.3, 203.9, 201.1 [L and C(3, 11, 12)]; 189.9 [C(10)]; 178.3 [C(15)]; 161.1, 160.4 [C(1, 13)]; 156.0 [C(21)]; 140.1
[C(19)]; 129.7 [C(9)]; 124.9 [C(18)]; 123.6 [C(20)]; 65.2 [C(2)]; 53.7 [C(4)]; 52.9, 52.2 [C(14, 16)]; 34.7, 26.9, 16.8, 11.6 [R′′]
4ik s
major
210.8, 209.4, 208.1 [L and C(3, 11, 12)]; 198.7 [C(10)]; 179.4 [C(15)]; 162.2, 161.4 [C(1, 13)]; 157.0 [(Ph)(Me)(H)C*-NC];
155.6 [C(21)]; 139.1 [C(19)]; 138.9, 129.7, 126.1, 122.3 [(Ph)(Me)(H)C*-NC]; 129.7 [C(9)]; 129.3 [C(18)]; 124.0 [C(20)];
59.2, 57.2 [C(2) and (Ph)(Me)(H)C*-NC]; 52.8, 51.9 [C(14, 16)]; 44.1 [C(4)]; 25.1 [(Ph)(Me)(H)C*-NC]; 21.7 [C(5)]
minor
210.9, 209.4, 208.2 [L and C(3, 11, 12)]; 198.9 [C(10)]; 179.1 [C(15)]; 162.3, 161.3 [C(1, 13)]; 157.0 [(Ph)(Me)(H)C*-NC];
155.6 [C(21)]; 139.1 [C(19)]; 138.9, 129.8, 126.0, 122.4 [(Ph)(Me)(H)C*-NC]; 129.7 [C(9)]; 129.3 [C(18)]; 124.0 [C(20)];
59.2, 57.1 [C(2) and (Ph)(Me)(H)C*-NC]; 52.8, 51.8 [C(14, 16)]; 44.1 [C(4)]; 25.4 [(Ph)(Me)(H)C*-NC]; 21.5 [C(5)]
5a k r
major
212.0, 210.1, 209.7 [L and C(11, 12)]; 175.8, 170.7 [C(1, 3, 13, 15)]; 155.6 [C(21)]; 138.3 [C(19)]; 124.4 [C(18)]; 123.1 [C(20)];
70.5 [C9)]; 70.0 [C(2)]; 56.9, 52.2 [C(4, 10, 14)]; 41.8, 31.2, 26.7, 26.4 [R]; 16.2 [C(5)]
minor
212.1, 210.1, 209.8 [L and C(11, 12)]; 174.1, 171.4 [C(1, 3, 13, 15)]; 155.6 [C(21)]; 138.1 [C(19)]; 124.4 [C(18)]; 123.1 [C(20)];
71.0 [C9)]; 67.3 [C(2)]; 55.5, 54.7, 52.2 [C(4, 10, 14)]; 39.8, 30.9, 30.5, 26.6 [R]; 17.5 [C(5)]
5a k s
major
210.1, 209.6, 207.6 [L and C(11, 12)]; 174.9 [C(15)]; 170.8, 170.7, 170.3 [C(1, 3, 13)]; 155.9 [C(21)]; 138.9 [C(19)]; 124.7
[C(18)]; 122.6 [C(20)]; 71.0 [C(2)]; 70.0 [C(10)]; 67.2 [C(9)]; 58.2 [C(4)]; 53.8, 52.6 [C(14, 16)]; 41.3, 31.2, 31.1, 26.8,
26.3 [R]; 15.9 [C(5)]
minor
210.1, 209.6, 207.6 [L and C(11, 12)]; 174.9 [C(15)]; 170.8, 170.7, 170.3 [C(1, 3, 13)]; 155.9 [C(21)]; 138.9 [C(19)]; 124.7
[C(18)]; 122.6 [C(20)]; 67.7 [C(2)]; 70.0 [C(10)]; 67.2 [C(9)]; 55.0 [C(4)]; 53.8, 52.6 [C(14, 16)]; 41.3, 31.2, 31.1, 26.8,
26.3 [R]; 15.9 [C(5)]
5a ls
major
210.2, 209.7, 207.0 [L and C(11, 12)]; 171.6, 170.7, 170.3, 169.5 [C(1, 3, 13, 15)]; 156.3 [C(21)]; 138.1 [C(19)]; 134.7 [R′];
130.9-124.6 [R′; C(18, 20)]; 82.3 [C(2)]; 77.8 [C(9)]; 69.6 [C(10)]; 56.3 [C(4)]; 53.2, 50.8 [C(14, 16)]; 43.2, 30.7, 29.8,
26.6, 26.1 [R]; 15.2 [R′′]
5a m r
major
212.6, 210.7, 210.4 [L and C(11, 12)]; 173.2, 172.2 [C(1, 3, 13)]; 152.1 [C(21)]; 138.0 [C(19)]; 124.1 [C(18)]; 121.7 [C(20)];
78.0 [C(2)]; 73.6 [C(9)]; 57.2, 55.1, 51.6 [C(4, 10, 14]; 40.0, 32.4, 29.2, 26.7, 26.6, 26.3 [R]; 19.2, 19.1 [R′ and R′′]
5a m s
major
210.8, 209.3, 207.4 [L and C(11, 12)]; 172.4, 171.7, 170.6, 170.4 [C(1, 3, 13, 15)]; 155.8 [C(21)]; 138.5 [C(19)]; 124.4 [C(18)];
121.4 [C(20)]; 73.9, 73.1, 71.7 [C(2, 9, 10)]; 55.4, 53.9, 51.8 [C(4, 14, 16)]; 39.7, 35.1-25.7 [R]; 19.2, 18.5 [R′ and R′′]
5bk r
major
211.9, 209.5, 209.4 [L and C(11, 12)]; 175.1 [C(3, 13)]; 169.3 [C(1)]; 154.4 [C(21)]; 141.3, 128.8-123.4 [R and C(18, 20)];
137.9 [C(19)]; 70.8 [C(9)]; 65.8 [C(2)]; 54.0 [C(4)]; 51.7, 48.6 [C(10, 14)]; 16.5 [C(5)]
minor
211.8, 209.6, 209.4 [L and C(11, 12)]; 174.8 [C(3, 13)]; 170.4 [C(1)]; 155.2 [C(21)]; 139.3, 128.8-123.4 [R and C(18, 20)];
137.8 [C(19)]; 70.6 [C(9)]; 65.8 [C(2)]; 54.8 [C(4)]; 52.0, 51.7 [C(10, 14)]; 17.1 [C(5)]
5bk s
major
210.3, 209.2, 207.5 [L and C(11, 12)]; 174.8, 172.3, 170.7, 169.2 [C(1, 3, 13, 15)]; 154.9 [C(21)]; 141.2 [R]; 137.4 [C(19)];
129.3-123.4 [C(18, 20) and R]; 68.6, 67.9, 66.3 [C(2, 9, 10)]; 53.9, 52.6, 49.4 [C(4, 14, 16)]; 16.9 [C(5)]
minor
210.2, 209.1, 207.5 [L and C(11, 12)]; 174.6, 171.8, 170.5, 170.4 [C(1, 3, 13, 15)]; 155.5 [C(21)]; 139.1 [R]; 138.4 [C(19)];
129.3-123.4 [C(18, 20) and R]; 69.5, 67.8, 67.6 [C(2, 9, 10)]; 52.9, 52.5, 49.4 [C(4, 14, 16)]; 17.0 [C(5)]

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2163
Ta ble 14 (Con tin u ed )
compd
13C NMR data
5blr
major
212.0, 210.5, 210.1 [L and C(11, 12)]; 175.4, 171.5, 168.5 [C(1, 3, 13)]; 155.6 [C(21)]; 143.6, 135.1, 130.9-123.8 [R and R′
and C(18-20)]; 82.6, 79.7 [C(2, 9)]; 56.1, 55.0, 51.1 [C(4, 10, 14)]; 23.4 [R′′]
minor
212.0, 210.5, 210.1 [L and C(11, 12)]; 175.4, 174.4, 168.5 [C(1, 3, 13)]; 155.5 [C(21)]; 142.5, 134.0, 130.9-123.8 [R and R′
and C(18-20)]; 82.6, 79.7 [C(2, 9)]; 56.0, 53.9, 51.0 [C(4, 10, 14)]; 19.1 [R′′]
5bls
major
210.3, 210.2, 207.1 [L and C(11, 12)]; 172.8, 171.1, 170.8, 168.7 [C(1, 3, 13, 15)]; 155.7 [C(21)]; 143.6, 135.1, 129.2-124.0
[R and R′; C(18, 20)]; 137.2 [C(19)]; 83.1, 66.3 [C(2, 9, 10)]; 56.7, 53.5, 51.4 [C(4, 14, 16)]; 23.6 [R′′]
minor
210.3, 210.2, 207.1 [L and C(11, 12)]; 172.8, 171.1, 170.8, 168.7 [C(1, 3, 13, 15)]; 155.7 [C(21)]; 143.6, 135.1, 129.2-124.0
[R and R′; C(18, 20)]; 137.2 [C(19)]; 78.3, 68.7 [C(2, 9, 10)]; 55.4, 53.5, 51.6 [C(4, 14, 16)]; 15.8 [R′′]
5bm r
major
212.5, 210.5, 210.0 [L and C(11, 12)]; 174.5, 172.7, 171.1 [C(1, 3, 13)]; 155.4 [C(21)]; 142.4, 128.9-126.6 [R]; 138.0 [C(19)];
123.8 [C(18)]; 121.9 [C(20)]; 76.5, 73.8 [C(2, 9)]; 57.4 [C(4)]; 53.3, 51.8 [C(10,14)]; 22.8, 18.6 [R′ and R′′]
minor
212.0, 210.3, 209.9 [L and C(11, 12)]; 173.4, 172.9, 171.3 [C(1, 3, 13)]; 155.7 [C(21)]; 142.2, 128.9-126.6 [R]; 138.5 [C(19)];
124.3 [C(18)]; 121.5 [C(20)]; 75.5, 73.6 [C(2, 9)]; 56.0 [C(4)]; 52.1, 51.7 [C(10, 14)]; 19.2, 18.2 [R′ and R′′]
5bm s
major
211.0, 209.2, 207.6 [L and C(11, 12)]; 172.3, 172.1, 171.2, 170.6 [C(1, 3, 13, 15)]; 156.6 [C(21)]; 142.5 [R]; 138.4 [C(19)];
129.8-121.0 [R and C(18, 20)]; 74.2, 66.3 [C(2, 9, 10)]; 53.9, 53.7, 51.6 [C(4, 14, 16)]; 22.7, 18.0 [R′ and R′′]
minor
210.4, 209.2, 207.5 [L and C(11, 12)]; 172.4, 172.0, 171.1, 170.2 [C(1, 3, 13, 15)]; 155.9 [C(21)]; 142.2 [R]; 139.0 [C(19)];
129.8-121.0 [R and C(18, 20)]; 74.2, 72.6, 72.4 [C(2, 9, 10)]; 53.9, 53.7, 51.6 [C(4, 14, 16)]; 18.6, 18.4 [R′ and R′′]
5ck r
major
211.9, 210.0, 209.7 [L and C(11, 12)]; 175.8, 174.1, 171.0 [C(1, 3, 13)]; 155.8 [C(21)]; 138.4 [C(19)]; 124.5 [C(18)]; 123.2
[C(20)]; 70.4 [C(9)]; 68.8 [C(2)]; 55.4 [C(4)]; 52.7, 51.7 [C(10, 14)]; 28.3, 17.2, 12.1 [R and R′′]
minor
212.0, 209.8, 209.7 [L and C(11, 12)]; 175.8, 174.4, 171.3 [C(1, 3, 13)]; 155.8 [C(21)]; 138.2 [C(19)]; 124.5 [C(18)]; 123.5
[C(20)]; 70.6 [C(9)]; 67.5 [C(2)]; 55.2 [C(4)]; 52.3 [C(10, 14)]; 26.7, 19.0, 11.7 [R and R′′]
5ck s
major
210.1, 209.4, 207.6 [L and C(11, 12)]; 174.8, 171.0, 170.7, 170.5 [C(1, 3, 13, 15)]; 156.0 [C(21)]; 139.0 [C(19)]; 124.8 [C(18)];
122.8 [C(20)]; 70.3 [C(10)]; 69.8 [C(2)]; 67.2 [C(9)]; 53.8, 53.7, 52.5 [C(4, 14, 16)]; 27.9, 12.1 [R]; 17.5 [R′′]
minor
210.2, 209.3, 207.7 [L and C(11, 12)]; 174.8, 171.3, 171.0, 170.7 [C(1, 3, 13, 15)]; 156.0 [C(21)]; 138.8 [C(19)]; 124.8 [C(18)];
123.1 [C(20)]; 70.3 [C(10)]; 69.8 [C(2)]; 67.5 [C(9)]; 53.8, 53.7, 52.5 [C(4, 14, 16)]; 26.5, 11.6 [R]; 18.6 [R′′]
5clr
major
211.5, 210.5, 210.0 [L and C(11, 12)]; 173.6, 171.8, 170.4 [C(1, 3, 13)]; 156.2 [C(21)]; 137.4 [C(19)]; 135.0, 129.1-124.4 [R′
and C(18, 20)]; 82.2 [C(2)]; 78.9 [C(9)]; 54.5, 53.1, 51.2 [C(4, 10, 14)]; 26.3, 17.2, 12.2 [R and R′′]
minor
211.6, 210.4, 210.0 [L and C(11, 12)]; 173.9, 171.7, 170.3 [C(1, 3, 13)]; 156.2 [C(21)]; 137.8 [C(19)]; 135.0, 129.1-124.4 [R′
and C(18, 20)]; 82.3 [C(2)]; 78.9 [C(9)]; 54.6, 52.9, 51.2 [C(4, 10, 14)]; 26.1, 15.0, 12.7 [R and R′′]
5cls
major
210.3, 209.7, 207.1 [L and C(11, 12)]; 171.1, 170.9 [C(1, 3, 13, 15)]; 166.2 [C(21)]; 137.8 [C(19)]; 135.3, 129.0-124.4 [R′ and
C(18, 20)]; 82.9, 78.1, 68.1 [C(2, 9, 10)]; 53.6, 53.4, 51.4 [C(4, 14, 16)]; 26.3, 17.4, 12.3 [R and R′′]
minor
210.3, 209.7, 207.1 [C(8, 11, 12)]; 171.1, 170.9 [C(1, 3, 13, 15)]; 166.2 [C(21)]; 138.2 [C(19)]; 135.3, 129.0-124.4 [R′ and
C(18, 20)]; 82.9, 78.1, 68.1 [C(2, 9, 10)]; 53.6, 53.4, 51.3 [C(4, 14, 16)]; 28.8, 19.9, 13.0 [R and R′′]
5cm r
major
212.0, 210.3, 209.8 [L and C(11, 12)]; 172.6, 172.2, 171.7[C(1, 3, 13)]; 155.4 [C(21)]; 138.0 [C(19)]; 124.0 [C(18)]; 121.2
[C(20)]; 76.3, 73.0 [C(2, 9)]; 56.5 [C(4)]; 51.1, 50.7 [C(10, 14)]; 25.8, 19.3, 16.1, 12.1, 10.1 [R and R′ and R′′]
minor
211.9, 210.3, 209.7 [L and C(11, 12)]; 172.6, 172.2, 171.9 [C(1, 3, 13)]; 155.3 [C(21)]; 138.3 [C(19)]; 124.0 [C(18)]; 121.3
[C(20)]; 76.3, 73.0 [C(2, 9)]; 56.6 [C(4)]; 51.1, 50.9 [C(10, 14)]; 27.5, 18.7, 18.2, 16.1, 10.7 [R and R′ and R′′]
5cm s
major
210.6, 209.6, 207.9 [L and C(11, 12)]; 172.8, 172.6, 170.7 [C(1, 3, 13, 15)]; 156.0 [C(21)]; 138.4 [C(19)]; 124.3 [C(18)];
121.0 [C(20)]; 73.7, 72.7, 68.4 [C(2, 9, 10)]; 53.8, 51.8, 51.7 [C(4, 14, 16)]; 26.4, 19.4, 16.8, 11.7 [R and R′ and R′′]
minor
210.7, 209.5, 207.9 [L and C(11, 12)]; 172.6, 172.5, 170.6, 170.5 [C(1, 3, 13, 15)]; 156.0 [C(21)]; 138.8 [C(19)]; 124.3 [C(18)];
121.1 [C(20)]; 73.7, 72.7, 68.4 [C(2, 9, 10)]; 53.8, 51.8, 51.7 [C(4, 14, 16)]; 27.9, 18.6, 18.3, 12.5 [R and R′ and R′′]
5d k r
major
211.2, 209.6, 209.1 [L and C(11, 12)]; 175.2 [C(3)]; 168.4 [C(1, 13)]; 155.6 [C(21)]; 137.9 [C(19)]; 124.1 [C(18)]; 122.5 [C(20)];
69.0 [C(9)]; 67.7 [C(2)]; 53.6, 45.1 [C(4, 10, 14)]; 33.0, 26.5, 17.1, 11.1 [R]
minor
211.2, 209.6, 209.1 [L and C(11, 12)]; 175.2 [C(3)]; 168.4 [C(1, 13)]; 155.6 [C(21)]; 137.9 [C(19)]; 124.1 [C(18)]; 122.5 [C(20)];
69.0 [C(9)]; 67.3 [C(2)]; 53.6, 44.7 [C(4, 10, 14)]; 33.0, 27.6, 17.2, 11.6 [R]
5d k s
major
209.8, 209.5, 207.2 [L and C(11, 12)]; 174.9, 171.9, 170.8, 168.2 [C(1, 3, 13, 15)]; 156.1 [C(21)]; 138.6 [C(19)]; 124.5 [C(18)];
122.4 [C(20)]; 69.6 [C(10)]; 67.7 [C(2)]; 66.4 [C(9)]; 53.8, 52.8 [C(14, 16)]; 45.3 [C(4)]; 33.0, 27.8, 17.4, 12.0 [R]
minor
209.8, 209.5, 207.2 [L and C(11, 12)]; 174.9, 171.5, 170.8, 168.2 [C(1, 3, 13, 15)]; 156.1 [C(21)]; 138.6 [C(19)]; 124.5 [C(18)];
122.4 [C(20)]; 69.5[C(10)]; 67.7 [C(2)]; 66.4 [C(9)]; 53.8, 52.8 [C(14, 16)]; 45.8 [C(4)]; 33.0, 26.7, 17.5, 11.5 [R′′]
5d lr
major
211.4, 210.3, 209.9 [L and C(11, 12)]; 171.3, 169.9 [C(1, 3, 13)]; 156.3 [C(21)]; 137.2 [C(19)]; 134.5, 128.9-124.1 [R′ and
C(18, 20)]; 81.4, 79.8 [C(2, 9)]; 53.7, 51.0 [C(4, 10, 14)]; 33.5, 27.7, 16.7, 11.7 [R]
minor
211.4, 210.3, 209.9 [L and C(11, 12)]; 171.3, 169.9 [C(1, 3, 13)]; 156.3 [C(21)]; 137.2 [C(19)]; 134.6, 128.9-124.1 [R′ and
C(18, 20)]; 81.4, 79.5 [C(2, 9)]; 53.7, 51.0 [C(4, 10, 14)]; 30.0, 27.5, 17.7, 11.7 [R]

2164 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
Ta ble 14 (Con tin u ed )
compd
13C NMR data
5d ls
major
210.2, 209.7, 207.0 [L and C(11, 12)]; 173.0, 171.3, 169.7 [C(1, 3, 13, 15)]; 156.5 [C(21)]; 137.6 [C(19)]; 135.0 [R′]; 130.9-
124.4 [R′ and C(18, 20)]; 82.8, 77.3, 68.0 [C(2, 9, 10)]; 53.7, 51.4, 49.0 [C(4, 14, 16)]; 33.8, 28.0, 17.5, 11.8 [R]
minor
210.2, 209.8, 207.0 [L and C(11, 12)]; 173.0, 171.3, 169.7 [C(1, 3, 13, 15)]; 156.5 [C(21)]; 137.6 [C(19)]; 135.0 [R′]; 130.9-
124.4 [R′ and C(18, 20)]; 82.8, 77.3, 68.0 [C(2, 9, 10)]; 53.7, 51.4, 49.0 [C(4, 14, 16)]; 33.5, 28.1, 18.0, 11.8 [R]
5d m r
major
211.5, 209.9, 209.3 [L and C(11, 12)]; 172.3, 171.7, 171.6 [C(1, 3, 13)]; 155.4 [C(21)]; 137.9 [C(19)]; 123.8 [C(18)]; 121.1
[C(20)]; 74.7, 72.7 [C(2, 9)]; 54.4, 51.0, 45.8 [C(4, 10, 14)]; 34.3, 27.2, 19.1, 17.2, 11.6 [R and R′]
minor
211.5, 209.9, 209.3 [L and C(11, 12)]; 172.3, 171.7, 171.6 [C(1, 3, 13)]; 155.4 [C(21)]; 137.9 [C(19)]; 123.8 [C(18)]; 121.1
[C(20)]; 74.7, 72.8 [C(2, 9)]; 54.4, 51.0, 45.3 [C(4, 10, 14)]; 35.0, 27.4, 19.1, 17.1, 11.5 [R and R′]
5d m s
major
210.0, 208.7, 207.2 [L and C(11, 12)]; 172.2, 171.5, 171.1, 170.9 [C(1, 3, 13, 15)]; 155.6 [C(21)]; 138.6 [C(19)]; 124.1 [C(18)];
120.8 [C(20)]; 77.4, 73.5, 70.9 [C(2, 9, 10)]; 53.5, 51.3 [C(14, 16)]; 45.2 [C(4)]; 34.1, 27.4, 18.9, 17.1, 11.7 [R and R′]
minor
210.0, 208.7, 207.2 [L and C(11, 12)]; 172.2, 171.5, 171.1, 170.9 [C(1, 3, 13, 15)]; 155.6 [C(21)]; 138.6 [C(19)]; 124.1 [C(18)];
120.8 [C(20)]; 77.4, 73.5, 70.9 [C(2, 9, 10)]; 53.5, 51.3 [C(14, 16)]; 45.9 [C(4)]; 35.4, 27.4, 18.9, 17.1, 11.7 [R and R′]
7a k s
major
206.0; 204.9; 203.4; 201.5 [L and C(3, 11, 12)]; 194.3 [C(10)]; 178.1 [C(15)]; 171.2 [C(1)]; 161.4 [C(13)]; 127.5 [C(9)]; 77.2
[C(4)]; 55.9 [C(2)]; 54.2; 43.2; 30.7-26.2 [R]; 53.2; 52.3 [C(14, 16)]; 44.9 [C(4)]; 21.6; 17.2 [C(5)]
minor
206.1; 204.6; 203.4; 201.6 [L and C(3, 11, 12)]; 193.4 [C(10)]; 178.1 [C(15)]; 171.2 [C(1)]; 161.3 [C(13)]; 127.7 [C(9)]; 77.0
[C(4)]; 56.0 [C(2)]; 54.3; 42.0; 30.7-26.2 [R]; 53.1; 52.3 [C(14, 16)]; 45.4 [C(4)]; 20.8; 18.7 [C(5)]
7a k sb
major
212.0-209.4 [C(3, 11, 12)]; 198.9 (21.5 Hz) [C(10)]; 179.2 [C(15)]; 170.2 [C(1)]; 161.8 [C(13)]; 128.5 (9.8 Hz) [C(9)]; 74.2
(6.0 Hz) [C(4)]; 55.9 [C(2)]; 54.2; 43.1; 34.7-23.1 [R]; 53.8; 52.9 [C(14, 16)]; 51.9 [C(4)]; 55.0 (8.0 Hz) [L]; 20.8; 17.2
[C(5)]
minor
212.0-209.4 [C(3, 11, 12)]; 198.1 (22.5 Hz) [C(10)]; 179.1 [C(15)]; 168.6 [C(1)]; 161.8 [C(13)]; 128.7 (8.3 Hz) [C(9)]; 72.9
(5.9 Hz) [C(4)]; 56.4 [C(2)]; 54.1; 43.0; 34.7-23.1 [R]; 53.9; 53.7 [C(14, 16)]; 51.8 [C(4)]; 56.1 (7.9 Hz) [L]; 18.7; 16.0
[R and C(5)]
7a m sb
major
211.5 (37.7 Hz), 210.5 (83.0Hz), 209.6 (22.6Hz) [C(3, 11, 12)]; 198.0 (15.1Hz)[C(10)]; 179.6 (7.5Hz), 179.3 (7.5Hz)
[C(1, 15)]; 162.5 [C(13]; 192.2 [C(9)]; 63.7 [C(2)]; 53.9 (9.1Hz) [L and C(4)]; 52.7, 51.8 [C(14, 16)]; 43.0, 30.7-26.4 [R];
19.4, 17.2 [R′′ and R′]
7bk s
major
206.2; 204.4; 203.4; 202.9 [L and C(3, 11, 12)]; 193.4 [C(10)]; 177.4 [C(15)]; 173.8 [C(1)]; 129.9-127.1;142.6; 140.2 [R];
161.1 [C(13)]; 127.8 [C(9)]; 73.3 [C(4)]; 56.3 [C(2)]; 52.8; 51.8 [C(14, 16)]; 51.1 [C(4)]; 23.0; 16.7 [C(5)]
minor
206.4; 203.0; 201.4; 200.3 [L and C(11, 12)]; 191.4 [C(10)]; 177.6 [C(15)]; 173.3 [C(1)]; 129.9-127.1;140.8; 140.5 [R];
160.4 [C(13)]; 127.8 [C(9)]; 74.0 [C(4)]; 56.4 [C(2)]; 52.1; 51.9 [C(14, 16)]; 50.9 [C(4)]; 22.8; 18.2 [C(5)]
7bk sb
major
211.3; 209.9; 207.4 [C(3, 11, 12)]; 195.5 [C(10)]; 179.0 [C(15)]; 173.5 [C(1)]; 129.6-126.6; 143.5; 140.4 [R]; 161.4 [C(13)];
128.6 [C(9)]; 71.1 (5.8 Hz) [C(4)]; 56.0 [C(2)]; 52.5; 51.5 [C(14, 16)]; 50.1 [C(4)]; 53.7 (8.3 Hz) [L]; 24.0; 16.8 [C(5)]
minor
211.3; 209.9; 207.4 [C(3, 11, 12)]; 195.5 [C(10)];178.9 [C(15)]; 170.6 [C(1)]; 129.6-126.6; 141.9; 141.3 [R]; 161.8 [C(13)];
129.4 [C(9)]; 72.5 (6.0 Hz) [C(4)]; 56.4 [C(2)]; 51.8; 51.4 [C(14, 16)]; 49.7 [C(4)]; 53.3 (8.0 Hz) [L]; 24.7; 18.3 [C(5)]
7bk sc
major
210.8; 209.6; 207.7 [C(3, 11, 12)]; 199.8 [C(10)]; 179.0 [C(15)]; 172.4 [C(1)]; 129.6-127.0; 141.8; 141.3 [R]; 160.8 [C(13)];
127.8 [C(9)]; 71.6 [C(4)]; 56.3 [C(2)]; 52.1; 51.8 [C(14, 16)]; 49.6 [C(4)]; 31.0; 58.3; 152.8 [L]; 22.6; 15.9 [C(5)]
minor
210.4; 209.3; 208.8 [C(3, 11, 12)]; 199.6 [C(10)]; 178.9 [C(15)]; 173.2 [C(1)]; 129.6-127.0; 141.9; 141.5 [R]; 161.5 [C(13)];
127.9 [C(9)]; 70.7 [C(4)]; 56.4 [C(2)]; 52.8; 51.5 [C(14, 16)]; 49.6 [C(4)]; 30.6; 58.3; 153.5 [L]; 22.5; 15.5 [C(5)]
7ik s
major
210.6; 210.2; 208.6 [C(3, 11, 12)]; 201.3 [C(10)]; 179.1 [C(15)]; 169.8 [C(1)]; 161.5 [C(13)]; 127.1 [C(9)]; 65.0 [C(4)]; 57.1
[C(2)]; 52.9; 52.0 [C(14, 16)]; 43.6 [C(4)]; 129.8; 129.4; 126.3; 126.1; 138.6; 54.9; 26.9 [L]; 24.7; 24.6; 23.6; 23.5; 22.6;
21.3 [R and C(5)]
minor
210.7; 210.1; 208.5 [C(3, 11, 12)]; 201.1 [C(10)]; 179.3 [C(15)]; 169.8 [C(1)]; 161.4 [C(13)]; 127.0 [C(9)]; 64.9 [C(4)]; 57.2
[C(2)]; 52.9; 51.9 [C(14, 16)]; 43.6 [C(4)]; 129.8; 129.4; 126.3; 126.1; 138.7; 54.9; 27.1 [L]; 24.7; 24.6; 23.6; 23.5; 22.6;
21.3 [R and C(5)]
8a ls
major
166.4, 163.5, 162.0, 156.7 [C(1, 3, 13, 15)]; 162.0, 156.7 [C(9, 10)]; 149.7 [C(21)]; 137.4 [C(19)]; 134.8, 130.1, 129.3, 128.7
[R′]; 125.1 [C(18)]; 124.5 [C(20)]; 68.6 [C(2)]; 53.8, 58.3, 53.2 [C(4, 14, 16)]; 42.6, 30.2, 27.0, 26.7, 26.3 [R]; 14.8 [R′′]
8bm r
major
168.9, 162.4, 156.7, 152.9 [C(1, 3, 9, 13)]; 149.4 [C(21)]; 137.0 [C(10)]; 135.6 [C(19)]; 141.8, 129.6-127.4 [R]; 123.7 [C(18)];
121.9 [C(20)]; 72.4 [C(2)]; 54.2, 53.2 [C(4, 14)]; 21.0, 19.6 [R′ and R′′]
minor
169.4, 162.4, 156.7, 152.9 [C(1, 3, 9, 13)]; 149.8 [C(21)]; 137.3 [C(10)]; 135.6 [C(19)]; 141.8, 129.6-127.4 [R]; 123. [C(18)];
121.5 [C(20)]; 73.0 [C(2)]; 53.2, 52.7 [C(4, 14)]; 21.1, 19.9 [R′ and R′′]
8bm s
major
165.4, 163.1, 161.7, 154.7 [C(1, 3, 13, 15)]; 151.6, 135.8 [C(9, 10)]; 149.0 [C(21)]; 140.8 [R]; 129.2-127.9 [R and C(19)];
124.9 [C(18)]; 123.1 [C(20)]; 71.3 [C(2)]; 54.6, 53.8, 53.7 [C(4, 14, 16)]; 21.0, 19.6 [R′ and R′′]
minor
165.9, 162.9, 161.6, 154.7 [C(1, 3, 13, 15)]; 151.5, 135.7 [C(9, 10)]; 149.0 [C(21)]; 141.0 [R]; 129.2-127.9 [R and C(19)];
124.9 [C(18)]; 123.1 [C(20)]; 71.3 [C(2)]; 54.6, 53.8, 53.7 [C(4, 14, 16)]; 21.3, 19.8 [R′ and R′′]

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2165
Ta ble 14 (Con tin u ed )
compd
13C NMR data
8cls
major
162.0, 156.6, 153.1 [C(1, 3, 13, 15)]; 165.6, 163.1 [C(9, 10)]; 149.7 [C(21)]; 137.3 [C(19)]; 135.1-128.7 [R′]; 124.3, 124.2
[C(18, 20)]; 69.1 [C(2)]; 53.3, 53.1 [C(4, 14, 16)]; 27.3, 11.6 [R]; 16.3 [R′′]
8cm r
major
162.5, 157.1, 152.6 [C(1, 3, 13)]; 168.6, 137.2 [C(9, 10)]; 149.5 [C(21)]; 135.9 [C(19)]; 123.7 [C(18)]; 121.5 [C(20)]; 71.8
[C(2)]; 52.6, 51.6 [C(4, 14)]; 27.0, 11.7 [R]; 20.9, 18.5 [R′ and R′′]
a
“Major” and “minor” identify the values for the major and minor diastereomers of the respective compound. Chemical shifts are in
ppm relative to Me4Si and measured in CDCl3 at 263 K and 75.47 MHz. Assignments use the atom numbering according to Scheme 2.
b
With L ) P(OMe)3. c With L ) tBu-NC.
tion of the diastereomer ratio by the integration of
corresponding signals. Protons H(1) and H(1′) in the
complexes with phenylethylimines show the largest shift
difference, which we ascribe to the anisotropy effect of
the phenyl rings of the R* group in 7/7′bk s.
In all cases the chemical shifts of H(2) for the MP-
derived complexes 5k r have lower ppm values then
those of the DMAD-derived complexes 5k s, because the
DMAD-derived complexes 5k s have two electron-
withdrawing ester groups, which deshield the H(2)
nuclei.
13C NMR of Com p lexes 4, 5, 7, a n d 8. J ust like
the 1H NMR spectra, the 13C NMR spectra show
sufficient shift differences for the two diastereomers in
4, 5, 7 and 8 to make them easily distinguishable. The
most remarkable change in the chemical shifts of the
complexes 4, 5, 7 and 8, as compared to those of 1 and
6 results from rehybridization of the former imine
carbon atom (C(2)) from sp2 to sp3.
After the cycloaddition reaction, the two diastereo-
mers of 4 and 7 show different chemical shifts for most
of their corresponding carbon nuclei. However, the
general appearance of the partial spectra of each dias-
tereomer resembles the general pattern of the bicyclo
[2.2.2] complexes that have been described in previous
parts of this series of articles. The resonance of the
intact imine carbon atom C(1) is shifted downfield from
ca. 143 ppm in 6k to ca. 170 ppm in 7, while the former
imine carbon atom C(2) is shifted upfield to ca. 56 ppm
as a consequence of its rehybridization from sp2 to sp3.
The resonances of the former acetylene sp-hybridized
carbon atoms are different as a consequence of the
cycloaddition reaction. The CO ligands in the complexes
4, 5, and 7 give three separate resonances, which
indicates rigidity around the iron atom on the NMR time
scale. The chemical shift of the terminal CO ligands
depends on the choice of the additional ligand. The
stronger σ-donation of (S)-R-methylbenzyl isocyanide,
t-Bu-NC, and P(OMe)3 as opposed to CO causes a
downfield shift with respect to the tricarbonyl com-
plexes.
In the compounds 8k r and 8m r the alkene proton
H(10) is shifted ca. 2.6 ppm downfield in comparison to
the corresponding complexes 5r . This proton has now
a chemical shift that is normally found for olefinic
protons. This confirms the liberation of the pyrrolinone
ligand from its iron complex.
3
In some compounds 8 the J coupling between H(20)
and H(21) is significantly smaller than in the corre-
sponding complexes 5, indicating a larger dihedral angle
between the C-H bonds as a consequence of the
distorted geometry of the pyridine ring. For compounds
8, the resonance of H(4) is shifted downfield in com-
parison with complexes 5.
Compounds 5a ls, 5a m , 5cl, 5cm r , and also 8a ls with
R* ) (()-sec-Bu (c) or (cHex)(Me)(H)C (a ) and R′ ) Me
(m ) or Ph (l) show resonances at negative ppm values.
These resonances belong to the protons at the carbon
atoms at the 1-position of the R group of the chiral
nitrogen substituent, i.e., the 1-ethyl or 1-cyclohexyl
protons. Such negative ppm values can only be ex-
plained by the anisotropy effect of an aromatic ring
current; i.e., a position above the plane of an aromatic
ring that gives the extra diamagnetic shielding. Since
the negative values are observed not only for the
compounds with R′ ) Ph but also for those with R′ )
Me, the anisotropy effect of the pyridine ring must be
responsible. A phenyl or methyl group at C(2), but not
a proton as in compounds 5k , enforce a conformation of
the R* substituent that brings the protons at the
1-position of R in a position above the plane of the
pyridine ring.
In the compounds 5a k and 5ck the Me groups (R′′)
of the R* substituent are positioned above the plane of
the pyridine ring. The protons of these Me groups
resonate, therefore, at lower ppm values, namely in the
region of 0.48-0.71 ppm. This is in contrast to the
chemical shifts found in 5a l and 5a m , which resonate
in the region 1.64-0.94 ppm. In compounds 5b (except
for 5bk r ) these protons resonate in the region 1.89-
1.63 ppm for the major diastereomer, whereas in the
minor diastereomer these resonances are found in the
region +0.45 to -0.76 ppm. The same trend is found
for 5cl and 5cm .
The reductive elimination of 4k to 5k has the follow-
ing spectroscopic consequences. Complexes 5 have ppm
values for their carbonyl resonances higher than those
of complexes 4. The reason is the change in oxidation
state from Fe(II) (4) to Fe(0) (5). This causes a decrease
in σ-donation/increase of π-acceptance from the CO
ligands to the metal in 5. The former acetylenic carbon
nuclei (C(10)) resonate around 190.5 ppm in complexes
4k , while in complexes 5 they are found at 54-74 ppm,
because only in 4k is C(10) is σ-bonded to the iron atom.
Also, the chemical shift of the bridgehead carbon nuclei
C(2) is influenced by this reductive elimination, by an
upfield shift of approximately 10 ppm in 5k s.
As in the 1H NMR spectra, comparison of the 13C
NMR spectra of compounds 5 and 8 very clearly shows
the loss of the metal fragment in 8. Not only are the
Fe(CO)3 carbonyl resonances absent in 8 but also the
olefinic carbon atoms C(9) and C(10) are shifted to lower
field by circa 70 ppm, indicating that the olefinic π-bond
in the pyrrolinone ring is no longer coordinated.
IR Sp ectr oscop y. The IR data of complexes 1 and
4-8 together with the elemental analyses and FAB
mass spectral data are collected in Tables 15 and 16.

2166 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
Ta ble 15. IR Da ta a for Com p lexes 1 a n d 6
ligands. J ust as in complexes 1 and 6, the differences
in the stretching frequencies of the CO ligands of the
two diastereomers of the cycloadducts are too small to
be resolved in CDCl3 solution.
The influence of the different ligands L on the ν(CO)
frequencies in 7 is clearly visible in the series 7bk s (with
L ) CO, t-Bu-NC, or P(OMe)3). The better σ-donating
capacities of the P(OMe)3 and the t-Bu-NC ligands result
in more π-back-donation and correspondingly lower CO
stretching frequencies.
compd
νCO (cm-1
)
compd
νCO (cm-1
)
1a k
1a l
2010 (s); 1941 (br)
2002 (s); 1932 (br)
2000 (s); 1930 (br)
2010 (s); 1940 (br)
2009 (s); 1936 (br)
2004 (s); 1934 (br)
2010 (s); 1941 (br)
2005 (s); 1936 (br)
1cm
1d k
1d l
1d m
6a k
6a m
6bk
6bm
2005 (s); 1937 (br)
2010 (s); 1942 (br)
2006 (s); 1938 (br)
2005 (s); 1935 (br)
2024 (s), 1949 (s, br)
2018 (s); 1945 (br)
2029 (s), 1952 (s, br)
2015 (s); 1945 (br)
1a m
1bk
1bl
1bm
1ck
1cl
a
Recorded in hexane.
The complexes 5 have lower CO stretching frequen-
cies than 4k , because the iron atom is reduced from
Fe(II) in 4 to Fe(0) in 5. Complexes 5s show more
σ-donation of the terminal CO ligands than the com-
plexes 5r , because 5s has two ester groups, which
increase the π-acidity of the organic part of 5s. In
comparison with the precursors 1, complexes 5 show
higher CO stretching frequencies. This means that the
organic part of 5, the pyrrolinone ligand, is a better
electron acceptor than the PyCa ligands.
The IR spectra of the complexes 1 and 6 show the
characteristic pattern for Fe(R-diimine)(CO)3 complexes
in the carbonyl region.6 The higher wavenumbers for
the CO stretching vibrations in the DAB complexes 6
indicate slightly less metal-CO π-back-donation than
the PyCa complexes 1. Although the complexes 1 and
6 exist as mixtures of two diastereomers, only one set
of vibrations is observed.
The consequence of the oxidative cycloaddition reac-
tion, in which the iron atom is oxidized from Fe(0) to
Fe(II) in the [2.2.2] bicyclic complexes 4k and 7, is
reflected in the higher CO stretching frequencies,
indicating an increase in the σ-donation or rather
diminished π-back-donation toward the terminal CO
Con clu sion s
The 1,3-dipolar cycloaddition reactions with the C2-
symmetric R*-DAB(H;H) ligands indicate that the ob-
Ta ble 16. IR Da ta , Elem en ta l An a lyses, a n d F AB Ma ss Da ta for Com p ou n d s 4, 5, 7 a n d 8
anal. (%)
a
compd
νCO (cm-1
)
Mb
Cobs (Ccalc
)
Hobs (Hcalc
)
Nobs (Ncalc)
4a sk
4bk s
4ck s
4ck sc
4d k s
4ik s
5a k r
5a k s
5a ls
5a m r
5a m s
5bk r
5bk s
5blr
2089 (s); 2030 (br)
2085 (s); 2030 (br)
2085 (s); 2030 (br)
2045 (s); 1993 (br)
2087 (s); 2035 (br)
527 (526)
54.55 (54.77)
55.21 (55.40)
49.65 (49.59)
46.37 (46.50)
5.07 (4.98)
3.91 (3.88)
4.31 (4.38)
5.19 (5.15)
5.28 (5.32)
5.38 (5.38)
6.18 (6.09)
4.86 (4.93)
569 (568)
2159 (br);d 2040 (s); 1996 (s)
2054 (s); 1990 (sh); 1973 (br)
2060 (s); 2002 (sh); 1984 (br)
2058 (s); 2000 (sh); 1979 (br)
2050 (s); 1989 (sh); 1971 (br)
2056 (s); 1993 (sh); 1976 (br)
2055 (s); 1992 (sh); 1975 (br)
2059 (s); 2000 (sh); 1983 (br)
469 (468)
527 (526)
54.64 (54.77)
59.00 (59.81)
4.90 (4.98)
5.34 (5.02)
5.40 (5.32)
5.12 (4.65)
463 (462)
539 (538)
597 (596)
477 (476)
535 (534)
415 (414)
473 (472)
491 (490)
549 (548)
429 (428)
5bls
2061 (s); 2001 (sh); 1983 (br)
60.29 (60.42)
4.12 (4.06)
4.58 (4.70)
5bm r
5bm s
5ck r
5ck s
5clr
2060 (s); 2000 (sh); 1981 (br)
2055 (s); 1992 (sh); 1974 (br)
2063 (s); 2003 (sh); 1984 (br)
2052 (s); 1988 (sh); 1973 (br)
2061 (s); 2000 (sh); 1983 (br)
2051 (s); 1988 (sh); 1971 (br)
2060 (s); 2000 (sh); 1981 (br)
2056 (s); 1993 (sh); 1976 (br)
2065 (s); 2005 (sh); 1983 (br)
50.60 (49.54)
53.17 (53.29)
50.44 (50.65)
4.26 (4.38)
4.75 (4.71)
4.58 (4.68)
5.88 (6.09)
6.50 (6.54)
5.82 (5.91)
5cls
5cm r
5cm s
5d k r
5d k s
5d lr
505 (504)
563 (562)
5d ls
5d m r
5d m s
7a k s
7a k sd
7a m s
7a m sc
7bk s
7bk sd
7bk se
7bm s
7ik s
2052 (s); 1990 (sh); 1973 (br)
2062 (s); 1991 (sh); 1984 (br)
2081 (s), 2028 (s, br)
2039 (s), 1987 (s, br)
2080 (s); 2026 (br)
2034 (s); 1982 (br)
2087 (s), 2031 (s, br)
2035 (s), 1988 (s, br)
2157 (s), 2040 (s), 1995 (s, br)
2082 (s); 2025 (br)
54.40 (54.32)
57.29 (57.34)
5.09 (5.02)
6.49 (6.54)
6.39 (6.33)
5.38 (4.78)
587 (586)
51.84 (50.91)
53.06 (52.79)
7.00 (7.48)
6.94 (6.95)
3.81 (4.24)
4.03 (4.10)
697 (696)
575 (574)
629 (629)f
2159 (s), 2040 (s), 1996 (s)
554 (553)
463 (462)
395 (394)
289 (288)
56.38 (56.43)
70.25 (70.11)
5.62 (5.65)
6.61 (6.54)
7.47 (7.59)
5.97 (6.06)
8a ls
8bm s
8cm s
a
b
Recorded in CDCl3. Observed (calculated) masses of the molecular ion (m/e); the values are based upon the 56Fe isotope. c With L′
) P(OMe)3. With L′ ) tBu-NC. e ν(CN). f Also observed are (M + tBu-NC) and (M + CO).
d

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2167
the solvent the crude product mixture was purified by column
chromatography. Elution with Et2O gave the two diastereo-
meric products (5k s) in the same diastereomeric ratio as in
the starting complexes 4k s. After evaporation of the solvent
the product is obtained as a yellow powder in 70% yield.
served diastereoselectivity is caused by a small differ-
ence in the rate constants of the cycloaddition reactions
to the imine re and si faces in the R*-DAB ligand in
6k . In contrast to the C2-symmetric case, the free
energies of activation in the non-C2-symmetric case for
the two different diastereomeric conformers of the 1,3-
dipolar species and their respective concentrations may
be quite different.
F or m a tion of F e(p yr r olin on e)(CO)3 Com p lexes (5r , 5ls,
a n d 5m s). A solution of 1 (ca. 0.7 mmol) in 20 mL of hexane
and 2-3 equiv of MP or 1.1 equiv (406 mg, 2.9 mmol) of DMAD
was stirred for 7 days at room temperature under an atmo-
sphere of CO. Washing with hexane and subsequent drying
in vacuo gave the products as yellow powders in yields of 70-
90%. For 5k r , 5ls, and 5m s, the products could be further
purified by column chromatography; elution with Et2O deliv-
ered a yellow fraction, which after evaporation of the solvent
gave the products as yellow powders in a yield of 70%. For
5lr and 5m r , elution with CH2Cl2 delivered a yellow fraction,
which after evaporation of the solvent gave the products as
yellow powders in yields of 80-90%.
F or m a tion of F e(CO)3([2.2.2]bic) Com p lexes 4ik s a n d
7ik s w ith L ) (S)-(P h )(Me)(H)C*NC. To a cooled (-30 °C)
solution of 1ik or 6ik (1.34 mmol) in 35 mL of hexane was
added 1.0 equiv (181 mg, 1.34 mmol) of (S)-(Ph)(Me)(H)C*NC,
followed by 1 equiv (191 mg, 1.34 mmol) of DMAD in 20 mL
of hexane/Et2O (3:1) over ca. 5 min. The reaction mixture was
warmed to room temperature and stirred for an additional 30
min. The precipitate was repeatedly washed with hexane and
dried in vacuo, giving a 1:1 mixture of the two diastereomers
of 4ik s and 7ik s in ca. 90% yield as a yellow powder.
Exp er im en ta l Section
Gen er a l In for m a tion . Reactions were performed under
an atmosphere of dry nitrogen using standard Schlenk tech-
niques. Silica gel for column chromatography (Kieselgel 60,
70-230 mesh, E. Merck, Darmstadt, Germany) was dried and
activated before use (vacuum, 160 °C, 16 h). Solvents were
carefully dried and distilled under nitrogen. Elemental analy-
ses were carried out by Dornis und Kolbe, Mikroanalytisches
Laboratorium, Mu¨lheim a.d. Ruhr, Germany. tert-Butyl iso-
cyanide was purchased from Fluka; DMAD, MP, (R/S)-cyclo-
hexylethylamine, (R/S)-phenylethylamine, (()-sec-butylamine,
(()-(2-methylbutyl)amine, glyoxal, methylglyoxal, pyridine-2-
carbaldehyde, 2-acetylpyridine, 2-benzoylpyridine, H2O2, and
P(OMe)3 were purchased from Aldrich and were used without
further purification. The chiral R*-DAB(H;R′) (S,S or R,R)16a
and R*,R′-PyCa (S or R)9e,16b ligands and their Fe(CO)3
complexes16c were prepared by following known methods. (S)-
phenylethyl isocyanide was prepared, with small modifica-
tions, according to the method of Ugi et al.16d
Syn th esis of Fe(CO)3([2.2.2]bic) (4aks-4dks, 7aks, 7am s,
7bk s, a n d 7bm s) in Hexa n e. To a cooled solution (T ) 238,
243, 253, 273, 298 K) of 1a k -d k or 6a k ,a m ,bk ,bm (4.01
mmol) in 20 mL of hexane was added over 5-10 min a solution
of 1.1 equiv (627 mg, 4.41 mmol) of DMAD in 20 mL of hexane/
Et2O (3:1) under an atmosphere of CO. After the mixture was
stirred for 15 min and subsequently warmed to room temper-
ature, the precipitate was repeatedly washed with hexane.
Drying in vacuo gave the products in 70% (7) and 95% (4)
yields as yellow powders. In the case of 4bk s the two
diastereomeric products can be separated by column chroma-
tography. Elution with Et2O yielded one diastereomer and
further elution with THF the other (the synthesis of 7bk s was
also done at 203 K).
Decom p lexa tion w ith Cl2 Ga s. Over a period of 5 s Cl2
gas was bubbled through a cooled solution (-78 °C) of 5l,m
(ca. 0.7 mmol) in 20 mL of Et2O/CH2Cl2 (1:1). Immediately a
yellow precipitate (FeCl2) was formed, which was filtered off.
The solution was washed with water and dried over MgSO4.
Evaporation of the solvent and subsequent addition of hexane
resulted in the formation of a white powder, which was dried
in vacuo. The 5-(2-pyridyl)pyrrolin-2-ones 8a ls, 8cls, 8bm r ,
8bm s, and 8cm r were isolated in yields of ca. 70%.
Decom p lexa tion w ith I2. To a cooled solution (-78 °C)
of 5l,m in 20 mL of Et2O was added 2 equiv of I2. The reaction
mixture was then warmed to room temperature and was
stirred for 1 h. The reaction mixture was washed with water
and dried over MgSO4. The resulting brown oils were identi-
fied as 8a ls, 8cls, 8bm r , 8bm s, and 8cm r (still containing
traces of I2).
Syn th esis of F e(CO)3([2.2.2]bic) (4bk s a n d 7bk s) in
CH3CN a n d THF . To a solution of 2.0 mmol of 1bk or 6bk
in 20 mL of THF (or acetonitrile) was added a solution of 1.0
equiv (284 mg, 2.0 mmol) of DMAD in 20 mL of THF (or
acetonitrile) over 5 min at room temperature. The mixture
was stirred for 15 min, followed by evaporation of the solvent.
The crude product was washed with hexane. After drying in
vacuo a yellow powder was obtained in 80-90% yield.
Rea ction of 1ck or 6 w ith DMAD in th e P r esen ce of
Differ en t Ad d ition a l Liga n d s L (P (OMe)3 or tBu NC).
Solutions of 0.151 mmol of 1ck or 6 in 20 mL of hexane were
cooled to T ) 238, 243, 253, 273, and 298 K, after which 1.0
equiv (0.151 mmol) of L was added. To this was added a
solution of 1.0 equiv (21.5 mg, 0.151 mmol) of DMAD in 20
mL of hexane/Et2O (4:1) over 10 min, and the mixture was
stirred for an additional 15 min. After it was warmed to room
temperature, the product was filtered off and washed three
times with 20 mL of hexane. After drying in vacuo a yellow
powder was obtained in 80-95% yield.
Decom p lexa tion w ith H2O2. To a cooled (0 °C) solution
of 5l,m (1.0 mmol) in 20 mL of methanol and 6 mL of H2O2
(30 wt % in H2O) was added 6 equiv of NaOH in 10 mL of
methanol over ca. 5 min. The reaction mixture was then
evaporated to dryness and extracted by 20 mL of Et2O.
Subsequent filtration gave a yellow solution, which was
washed with a saturated NH4Cl solution in water. The organic
layer was dried over MgSO4. After removal of the Et2O, 20
mL of hexane was added, which resulted in the precipitation
of 8a ls, 8cls, 8bm r , 8bm s, and 8cm r in the form of white
powders, in yields of 60-80%.
Decom p lexa tion by Air Oxid a tion . For the decomplex-
ation by reaction in air, complexes 5 were dissolved in a
suitable solvent (toluene, THF, or chloroform) and were stirred
for several days at room temperature, until 5 was completely
decomposed to 8 (ca. 6 days). Filtration of the formed iron
oxides and removal of the solvent in vacuo gave 8ck r , 8a ls,
8cls, 8bm r , 8bm s, and 8cm r as white powders in yields of
70-80%.
Con ver sion of 4k s to F e(p yr r olin on e)(CO)3 Com p lexes
(5k s) u n d er CO P r essu r e. A solution of 3.7 mmol of 4a k s-
d k s in 100 mL of toluene was put under 50 bar of CO pressure
and stirred at 70-90 °C for one night. After evaporation of
Decom p lexa tion w ith Me3NO. A solution of ca. 0.4 mmol
of 5l,m in toluene was cooled to -78 °C. Subsequently, 10
equiv (4 mmol) of dried Me3NO was added. After it was
warmed to room temperature, this mixture was stirred for ca.
(16) (a) tom Dieck, H.; Dietrich, J . Chem. Ber. 1984, 117, 694. (b)
Brunner, H.; Riepl, G.; Benn, R.; Rufinska, A. J . Organomet. Chem.
1983, 253, 93. (c) Fru¨hauf, H.-W.; Landers, A.; Goddard, R.; Kru¨ger,
C. Angew. Chem. 1978, 90, 56. (d) Ugi, I.; Meyr, R.; Lipinsky, M.;
Bodesheim, F.; Rosendahl, F. Org. Synth. 1961, 41, 13.
90 min. Filtration resulted in
a yellow solution. After
evaporation of the toluene, the product was redissolved in CH2-
Cl2. This solution was washed with water. Drying over
MgSO4 and subsequent addition of hexane resulted in white

2168 Organometallics, Vol. 15, No. 8, 1996
Feiken et al.
Ta ble 17. Cr ysta llogr a p h ic Da ta a n d Deta ils of Da ta Collection a n d Refin em en t of 4a k s, 5ck s,
7a k s, a n d 8a ls
4a k s
5ck s
7a k s
8a lsa
Crystal Data
C20H20N2O8Fe‚CH2Cl2
472.2
monoclinic
P21/c (No. 14)
8.186(1)
12.0260(6)
25.257(2)
91.826(9)
2485.2(5)
4
1.49
1144
73.31
0.03 × 0.70 × 0.80
Data Collection
248
formula
mol wt
cryst syst
space group
a (Å)
C
24H26N2O8Fe
C28H38N2O8Fe
586.4
orthorhombic
P212121 (No. 19)
13.151(5)
C27H30N2O5‚C4H10
536.67
orthorhombic
P212121 (No. 19)
9.045(2)
O
526.33
orthorhombic
P212121 (No. 19)
10.4959(8)
14.4943(15)
16.428(2)
b (Å)
c (Å)
14.026(7)
16.069(4)
13.1560(17)
25.279(3)
â (deg)
V (Å)3
Z
2499.2(4)
4
1.399
1096
2964(2)
4
1.314
1240
3008.1(8)
4
1.185
1152
6.7
D
calc (g cm-3
)
F(000)
µ (cm-1
)
6.5
5.5
cryst size (mm3)
0.20 × 0.25 × 0.50
0.20 × 0.25 × 0.75
0.20 × 0.40 × 0.80
temp (K)
150
150
295
θ
min, θmax (deg)
1.9, 25.0
Mo KR, 0.710 73 Å
ω
-5,1,1
4719
4388
3.5, 70
Cu KR, 1.5418 Å
ω/2θ
0,3,2, 1,1,-5
5036
5036
1.9, 25.0
Mo KR, 0.710 73 Å
ω
-4,4,4
5684
5221
1.8, 74.9
Cu KR, 1.541 84 Å
ω/2θ
-2,-1,-3, -3,-2,-1, 0,-6,-2
6790
6185
radiation
scan type
ref rflns
total no. of data
total no. of unique data
no. of obs data
R(int)
3546 [I > 2σ(I))
0.1500
0.1269
0.0024
Refinement
0.71-1.64
DIFABS corr range
no. of refined params
Rb (no of data)
0.628-1.948
0.849-1.464
319
396
356
310
0.1025 (2549 > 4σ(Fo)) 0.087 (3546 > 2σ(I))
0.084 (3138 Fo > 4σ(Fo)) 0.038 (5136 > 4σ(Fo))
c
Rw
0.113
wR2,d (no of data)
0.3906 (4331)
0.203 (5221)
0.99
0.109 (6185)
1.007
S
1.134
0.47
wte
σ2(Fo2) + (0.1362P)
0.000
σ2(F2) + (0.088P)2
0.001
σ2(Fo2) + (0.0703P)2
0.005
(∆/σ)max in final cycle
0.69
-0.9, 1.1
min and max resd dens
-0.86, 1.41
-0.42, 0.48
0.11, -0.16
(e Å-3
)
Flack param
-0.07(7)
0.08(5)
0.47(18)
a
b
d
Including disordered solvent contribution (diethyl ether). R1) ∑||Fo| - |Fc||/∑|Fo|. c Rw ) [∑[w(||Fo| - |Fc||)2]/∑[w(Fo2)]]0.5
.
wR2 )
[∑[w(Fo - Fc2)2/∑(Fo2)2]]0.5
.
e P ) (Max(Fo2), 0) + 2Fc2)/3.
2
powders of 8a ls, 8cls, 8bm r , 8bm s, and 8cm r in yields of ca.
80% after drying in vacuo.
collection and refinement are collected in Table 17. Data were
corrected for Lp effects and for a linear decay of 8% of the
periodically measured reference reflection. An empirical
absorption/extinction correction was applied (DIFABS19 as
implemented in PLATON20). The structure was solved by
automated Patterson methods and subsequent difference
Fourier techniques (DIRDIF-92).21 Refinement on F2 was
carried out by full-matrix least-squares techniques (SHELXL-
9322); no observance criterion was applied during refinement.
Non-hydrogen atoms were refined with anisotropic thermal
parameters. The hydrogen atoms were refined with a fixed
isotropic thermal parameter related to the value of the
equivalent isotropic thermal parameter of their carrier atoms
by a factor of 1.5 for the methyl hydrogen atoms and a factor
of 1.2 for the other hydrogen atoms. Weights were optimized
in the final refinement cycles. The structure contains a tiny
void of 8.5 Å3 at 0.042, 0.757, and 0.649. As expected, no
significant residual density was found in that area (PLATON/
SQUEEZE).23 Geometrical calculations and illustrations were
performed with PLATON;20 all calculations were performed
on a DEC5000/125.
Decom p lexa tion w ith CO. A solution of 5l,m in THF or
toluene was stirred at 50 bar of CO at 140 °C for one night.
The formed Fe(CO)5 and the solvent were removed by evapo-
ration in vacuo, which resulted in a tar. Addition of hexane
and drying in vacuo gave the pyrrolinones 8a ls, 8cls, 8bm r ,
8bm s, and 8cm r as white powders in yields of 40-50%.
Deter m in a tion of th e Dia ster eom er ic Ra tio. For this
purpose, the cycloaddition products from the reactions de-
scribed above were not worked up by filtration and washing;
instead, the crude reaction mixture after the cycloaddition
reaction was evaporated to dryness. In all cases yellow
powders were obtained. The diastereomeric ratio was deter-
mined with 1H or 31P NMR, by integration of sufficiently
separated signals of the two diastereomers (cf. Figure 9). The
reproducibility within a series of spectra was found to be better
than 2%.
X-r a y Str u ctu r e Deter m in a tion of 4a k s. An orange
crystal (0.20 × 0.25 × 0.50 mm3, cut to size and covered by
inert oil) was mounted on a Lindemann-glass capillary and
transferred into the cold nitrogen stream on an Enraf-Nonius
CAD4-T diffractometer on a rotating anode. Accurate unit-
cell parameters and an orientation matrix were determined
from the setting angles of 25 reflections (SET4)17 in the range
9.9° < θ < 14.0°.
(18) Spek, A. L. J . Appl. Crystallogr. 1988, 21, 578.
(19) Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39, 158.
(20) Spek, A. L. Acta Crystallogr. 1990, A46, C34.
(21) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garc´ıa-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF Programsystem, Technical Report of the Crystallography
Laboratory, University of Nijmegen, Nijmegen, The Netherlands, 1992.
(22) Sheldrick, G. M. SHELXL-93 Program for Crystal Structure
Refinement; University of Go¨ttingen, Go¨ttingen, Germany, 1993.
(23) Spek, A. L. Am. Crystallogr. Assn. Abstracts 1994, 22, 66. See
also: van der Sluis, P.; Spek, A. L. Acta Crystallogr. 1990, A46, 194.
The unit-cell parameters were checked for the presence of
higher lattice symmetry.18 Crystal data and details on data
(17) de Boer, J . L.; Duisenberg, A. J . M. Acta Crystallogr. 1984, A40,
C410.

1,3-Dipolar Cycloaddition to the FesNdC Fragment
Organometallics, Vol. 15, No. 8, 1996 2169
X-r a y Str u ctu r e Deter m in a tion of 5ck s. A yellow
crystal with approximate dimensions 0.03 × 0.70 × 0.80 mm3
was used for data collection on an Enraf-Nonius CAD-4
diffractometer with graphite-monochromated Cu KR radiation
and ω-2θ scan. A total of 5036 unique reflections was
measured within the ranges 0 e h e 9, 0 e k e 14, -30 e l e
30. Of these, 3546 were above the significance level of
finement on F2 was carried out by full-matrix least-squares
techniques (SHELXL-9322); no observance criterion was ap-
plied during refinement. All non-hydrogen atoms were refined
with anisotropic thermal parameters. The hydrogen atoms
were refined with a fixed isotropic thermal parameter amount-
ing to 1.5 and 1.2 times the value of the equivalent isotropic
thermal parameter of their carrier atoms, for the methyl
hydrogen atoms and all other hydrogen atoms, respectively.
Weights were optimized in the final refinement cycles. The
structure contains a small void of 31 Å3 at 0.146, 0.727, 0.328.
However, no significant residual density was found in that
area (PLATON/SQUEEZE23). Neutral atom scattering factors
and anomalous dispersion corrections were taken from ref 28.
2.5σ(I). The maximum value of (sin θ)/λ used was 0.61 Å-1
.
Two reference reflections (032, 1,1,-5) were measured hourly
and showed no decrease during the 60 h collecting time. Unit-
cell parameters were refined by a least-squares fitting proce-
dure using 23 reflections with 80 e 2θ e 86°. Corrections for
Lorentz and polarization effects were applied. The structure
was solved by direct methods. After isotropic refinement a
∆F synthesis revealed three peaks, which could be interpreted
as dichloromethane, one of the solvents used in the crystal-
lization of the compound. The hydrogen atoms were calcu-
lated. Full-matrix least-squares refinement on F, anisotropic
for the non-hydrogen atoms and isotropic for the hydrogen
atoms, with the latter restrained in such a way that the
distance to their carrier atoms remained constant at ap-
proximately 1.09 Å, converged to R ) 0.087, Rw ) 0.113, and
(∆/σ)max ) 0.69. An empirical absorption correction (DIFABS)19
was applied, with coefficients in the range of 0.71-1.64. The
secondary isotropic extinction coefficient24 was refined to Ect
) 0.07(2). A final difference Fourier map revealed a residual
electron density between -0.9 and 1.1 e Å-3 in the vicinity of
the heavy atom. Scattering factors were from Cromer and
Mann.25 The anomalous scattering of Fe was taken into
account. All calculations were performed with XTAL,26 unless
stated otherwise. Crystal data and numerical details of the
structure determination are given in Table 17.
X-r a y Str u ctu r e Deter m in a tion of 8a ls. A colourless
crystal (0.20 × 0.40 × 0.80 mm3, cut to size) was mounted on
a Lindemann-glass capillary and transferred to an Enraf-
Nonius CAD-4F diffractometer. Accurate unit cell parameters
and an orientation matrix were determined from the setting
angles of 25 reflections (SET4)17 in the range 17.8° < θ < 23.5°.
Reduced-cell calculations did not indicate higher lattice sym-
metry.18 In Table17 crystal data and details on data collection
and refinement are shown. Data were corrected for Lp effects
and for a linear decay of 1% of the periodically measured
reference reflections. The structure was solved by automated
direct methods (SHELXS86).27 Refinement on F2 was carried
out by full-matrix least-squares techniques (SHELXL-93);22 no
observance criterion was applied during refinement. Non-
hydrogen atoms were refined with anisotropic thermal pa-
rameters. The hydrogen atoms were refined with a fixed
isotropic thermal parameter related to the value of the
equivalent isotropic thermal of their carrier atoms by a factor
of 1.5 for the methyl hydrogen atoms and a factor of 1.2 for
the other hydrogen atoms. It was not possible to determine
the correct enantiomer through the final Flack absolute
structure parameter (0.47(18)). In four voids in the unit cell
of an area of 179 Å3 an electron count was encountered
(PLATON/SQUEEZE),20,21 probably diethyl ether. Weights
were optimized in the final refinement cycles. Neutral atom
scattering factors and anomalous dispersion corrections were
taken from ref 28. Geometrical calculations and illustrations
were performed with PLATON;19 all calculations were per-
formed on a DEC5000/125.
X-r a y Str u ctu r e Deter m in a tion of 7a k s. Crystals were
grown from a saturated Et2O/CH2Cl2 (3:1) solution at -20 °C.
A crystal with approximate dimensions 0.20 × 0.25 × 0.75
mm3 was mounted on
a Lindemann-glass capillary and
transferred into the cold nitrogen stream on an Enraf-Nonius
CAD4-T diffractometer on a rotating anode. Crystals were
found to reflect poorly, with broad, structured reflection
profiles. Accurate unit-cell parameters and an orientation
matrix were determined from the setting angles of 25 well-
centered reflections (SET4) in the range 9.8° < θ < 13.8°. The
unit-cell parameters were checked for the presence of higher
lattice symmetry.18 Crystal data and details on data collection
and refinement are shown in Table 17. Data were corrected
for Lp effects. An empirical absorption/extinction correction
was applied (DIFABS19 as implemented in PLATON20). The
structure was solved by automated Patterson methods and
subsequent difference Fourier techniques (DIRDIF-92).21 Re-
Ackn owledgm en t. Financial support from the Neth-
erlands Foundation of Chemical Research (SON) with
financial aid from the Netherlands Organization for
Scientific Research (NWO) is gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Tables giving full
details of crystallographic parameters, final coordinates, ther-
mal parameters, bond distances, bond angles, and torsion
angles (except for 5ck s) for 4a k s, 5ck s, 7a k s, and 8a ls (32
pages). Ordering information is given on any current mast-
head page.
(24) (a) Zachariasen, W. H. Acta Crystallogr 1967, A23, 558. (b)
Larson, A. C. The Inclusion of Secondary Extinction in Least-Squares
Refinement of Crystal Structures; In Crystallographic Computing;
Ahmed, F. R., Hall, S. R., Huber, C. P., Eds.; Munksgaard: Copen-
hagen, Denmark, 1969; p 291.
(25) (a) Cromer, D. T.; Mann, J . B. Acta Crystallogr. 1968, A24, 321.
(b) Cromer, D. T.; Mann, J . B. In International Tables for X-ray
Crystallography; Kynoch Press: Birminghem, U.K., 1974; Vol. IV, p
55.
OM950922O
(26) Hall, S. R.; Flack, H. D.; Stewart, J . M. In XTAL3.2 Reference
Manual; Universities of Western Australia, Geneva, and Maryland,
1992.
(28) Wilson, A. J . C., Ed. International Tables for Crystallography;
(27) Sheldrick, G. M. SHELXS86 Program for Crystal Structure
Determination, University of Go¨ttingen, Go¨ttingen, Germany, 1986.
Kluwer Academic Publishers: Dordrecht, The Netherlands, 1992; Vol.
C.