Control of the regioselectivity in catalytic transformations involving amphiphilic bis-allylpalladium intermediates: Mechanism and synthetic applications

Article abstract of DOI:10.1021/jo001374d

Various dialkyl-substituted allyl Chloride derivatives (2d-i) undergo regioselective palladium-catalyzed coupling reactions with allylstannanes (1a,b) and benzylidenemalonitrile (4), providing functionalized 1,7-octadienes in good yield. The catalytic reaction proceeds through an unsymmetrical amphiphilic bis-allylpalladium intermediate. An introductory electrophilic attack on the terminal position of the unsubstituted allyl moiety is followed by a nucleophilic attack on the alkyl-substituted allyl ligand. A theoretical analysis was performed by applying density functional theory at the B3PW91/DZ+P level to study the substituent effects on the electrophilic attack. According to the theoretical results, the high regioselectivity can be ascribed to the electronic effects of the alkyl substituents: The terminal alkyl groups destabilize the η¹,η³-bis-allylpalladium intermediate of the reaction; in addition, the alkyl substitution increases the activation, barrier for the electrophilic attack.

Full text of DOI:10.1021/jo001374d

1
686
J . Org. Chem. 2001, 66, 1686-1693
Con tr ol of th e Regioselectivity in Ca ta lytic Tr a n sfor m a tion s
In volvin g Am p h ip h ilic Bis-a llylp a lla d iu m In ter m ed ia tes:
Mech a n ism a n d Syn th etic Ap p lica tion s
Niclas Solin, Sanjay Narayan, and K a´ lm a´ n J . Szab o´ *,†
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University,
S-106 91 Stockholm, Sweden
kalman@organ.su.se
Received September 15, 2000
Various dialkyl-substituted allyl chloride derivatives (2d -i) undergo regioselective palladium-
catalyzed coupling reactions with allylstannanes (1a ,b) and benzylidenemalonitrile (4), providing
functionalized 1,7-octadienes in good yield. The catalytic reaction proceeds through an unsym-
metrical amphiphilic bis-allylpalladium intermediate. An introductory electrophilic attack on the
terminal position of the unsubstituted allyl moiety is followed by a nucleophilic attack on the alkyl-
substituted allyl ligand. A theoretical analysis was performed by applying density functional theory
at the B3PW91/DZ+P level to study the substituent effects on the electrophilic attack. According
to the theoretical results, the high regioselectivity can be ascribed to the electronic effects of the
1
3
alkyl substituents: The terminal alkyl groups destabilize the η ,η -bis-allylpalladium intermediate
of the reaction; in addition, the alkyl substitution increases the activation barrier for the electrophilic
attack.
In tr od u ction
Allylpalladium chemistry has become one of the most
are both electrophilic and nucleophilic), exceptionally
useful reagents in organic synthesis.
Recently, Yamamoto and co-workers reported a syn-
thetically useful reaction in which the bis-allylpalladium
intermediate was formed from a mixture of allyltribu-
tylstannane (1a ) and allyl chloride (2a ) in the presence
of a palladium catalyst (eq 1). This bis-allylpalladium
6
successful areas of organometallic catalysis due to its
remarkable capacity for continuous renewal. Catalytic
3
transformations involving nucleophilic attack on (η -
allyl)palladium intermediates have been widely applied
in a number of important chemical processes1 including
allylic substitution and the oxidation of alkenes and
conjugated dienes. However, recently, catalytic transfor-
mations proceeding through an initial electrophilic attack
-5
on bis-allylpalladium complexes have attracted much
attention.6
-12
Furthermore, it has been demonstrated
that, under catalytic conditions, bis-allylpalladium com-
plexes can undergo an initial electrophilic attack on one
of the allyl moieties followed by a nucleophilic attack on
the other.6 Thus, bis-allylpalladium intermediates can
,11
6
be classified as catalytic amphiphilic species (i.e., they
†
Fax: +46-8-15 49 08.
(1) Tsuji, J . Palladium Reagents and Catalysis: Innovations in
Organic Synthesis; Wiley: Chichester, 1995; Chapters 3 and 4.
2) Godleski, S. A. Comprehensive Organic Synthesis; Trost, B. M.,
Fleming, I., Ed.; Pergamon Press: New York, 1991; Vol. 4, Chapter
(
3
.3.
(
3) Harrington, P. J . Comprehensive Organometallic Chemistry II;
intermediate (3, Scheme 1) is attacked by an activated
olefin electrophile, such as benzylidenemalonitrile (4),
after which a nucleophilic attack takes place on the
(mono-) allylpalladium complex formed (Scheme 2), af-
fording a 1,7-octadiene derivative (5). Similar processes
Abel, E. W., Gordon, F., Stone, A., Wilkinson, G., Puddephatt, R. J .,
Eds.; Elsevier: New York, 1995; Vol. 12, p 797.
(
4) B a¨ ckvall, J .-E. Metal-catalyzed Cross Coupling Reactions;
VCH: Weinheim, 1998; p 339.
(
5) Trost, B. M. Acc. Chem. Res. 1980, 13, 385.
(6) Nakamura, H.; Shim, J .-G.; Yamamoto, Y. J . Am. Chem. Soc.
1
1
1
997, 119, 8113.
7) Nakamura, H.; Nakamura, K.; Yamamoto, Y. J . Am. Chem. Soc.
998, 120, 4242.
8) Nakamura, K.; Nakamura, H.; Yamamoto, Y. J . Org. Chem.
999, 64, 2614.
using arynes (eq 2) and carbon dioxide (eq 3) instead of
(
13,14
4
have also been reported.
In these publications it was
also pointed out that using a different substituent pattern
on the allyl chloride and allylstannane components leads
to a mixture of isomeric products. When 1a was reacted
(
(9) Ohno, K.; Tsuji, J . Chem. Commun. 1971, 247.
(10) Kiji, J .; Yamamoto, K.; Tomita, H.; Furukawa, J . J . Chem. Soc.,
(13) Yoshikawa, E.; Radhakrishnan, K. V.; Yamamoto, Y. Tetrahe-
dron Lett. 2000, 41, 729.
5
1, 2375.
(14) Franks, R. J .; Nicholas, K. M. Organometallics 2000, 19, 1458.
1
0.1021/jo001374d CCC: $20.00 © 2001 American Chemical Society
Published on Web 02/03/2001

Regioselective Control of Bis-allylpalladium Intermediates
J . Org. Chem., Vol. 66, No. 5, 2001 1687
Sch em e 1
Sch em e 3
Sch em e 2
attack by 4, the bis-allylation reaction can afford two
different isomeric products (Scheme 3). It is interesting
to note that the regioselectivity of the electrophilic attack
cannot simply be improved by employing the steric effects
of the alkyl substituent (eqs 4-6) since the 2-methylallyl
and the parent allyl moieties have a similar reactivity.
Since the above three-component catalytic procedures
have great synthetic potential, improvement of the re-
giocontrol would considerably enhance the synthetic
utility of these reactions. The present study was under-
taken to investigate those steric and electronic effects
that are responsible for the development of regioselec-
tivity. In this paper we present a substituent pattern,
which leads to highly regioselective three-component
coupling with alkylallyl chlorides, allylstannanes, and 4.
The synthetic studies are also combined with theoretical
calculations to gain a better understanding of the reaction
mechanism of the catalytic procedure.
with methylallyl chloride (2b) in the presence of a
palladium catalyst and aryne, a mixture of benzene
derivatives with totally random allylic-allylic addition
was obtained (eq 4).13 Palladium-catalyzed mixed car-
Exp er im en ta l Stu d ies
Th r ee-Com p on en t Cou p lin g Rea ction w ith Alk y-
la llyl Ch lor id e Der iva tives. As mentioned above, the
three-component coupling reaction of methylallyl chloride
(
2b), 1a , and 4 in the presence of a palladium catalyst
results in a mixture of four products (eq 6). Using
-chlorobutene (2c) in place of 2b also leads to a complex
reaction mixture including at least three different cross-
coupling products and homo-coupling products (eq 7).
3
boxylation between 1a and 2b results in a nearly statisti-
cal mixture of allyl esters, including all possible homo-
and cross-coupling products (eq 5).14 We have also found
that in the three-component coupling reaction of 1a , 2b,
and 4 a statistical mixture of 1,7-octadiene derivatives
was formed (eq 6).
Formation of the two different cross-coupling products
However, when we employed 4-alkyl-substituted crotyl
chloride derivatives (2d -i) with 1a and 4, just one cross-
coupled product was formed (Table 1, entries 1-6) with
a remarkably high regioselectivity (eq 8) and in good
yield. Furthermore, in these reactions 5 and other homo-
coupling products were not formed. Although, the regio-
and chemoselectivity of the reaction is very high, the
diastereoselectivity is poor as the different diastereomers
formed in a ratio of about 1:1.
Using methylallylstannane (1b) and 2b, the expected
homo-coupled product (6) was formed (entry 7) in good
yield. When 1b was reacted with 2d -i, the very high
regioselectivity was maintained (entries 8-13), but 6 was
also formed about 1-3%. However, this small amount of
in these reactions (eqs 4-6) can be easily explained by
6
,15,16
the accepted mechanism of the catalytic process.
Yamamoto and co-workers have shown15 that bis-al-
lylpalladium complexes (3) can be generated from a
mono-)allylpalladium complex and 1a . In the coupling
(
reaction of 1a , 2b, and 4, the Pd(0) catalyst undergoes
oxidative addition to 2b, generating a (mono-)allylpalla-
dium complex that reacts with 1a , affording the unsym-
metrical bis-allylpalladium complex 3c (Scheme 3). De-
pending on the location of the introductory electrophilic
(
15) Nakamura, H.; Iwama, H.; Yamamoto, Y. J . Am. Chem. Soc.
996, 118, 6641.
16) Szab o´ , K. J . Chem. Eur. J . 2000, 6, 4413.
1
(

1
688 J . Org. Chem., Vol. 66, No. 5, 2001
Solin et al.
Ta ble 1. P a lla d iu m -Ca ta lyzed Th r ee-Com p on en t
reactions proceed with the same selectivity when a
mixture of 2f-i and their corresponding allylic isomers
are used as the chloride component.
a
Cou p lin g Rea ction s of 1a ,b, 2d ,i, a n d 4
Regioselectivity of th e Electr op h ilic a n d Nu cleo-
p h ilic Atta ck . The very high regioselectivity is a syn-
thetically useful feature of the above three-component
coupling reactions (eq 8). The possible pathways involving
the different electrophilic and nucleophilic attacks are
given in Scheme 4. The first step is an oxidative addition
of the palladium(0) catalyst to 2d -i (or the corresponding
allylic isomers), which results in (mono-)allylpalladium
complex 19. This complex reacts with 1a ,b, giving the
1
3
unsymmetrical bis-allylpalladium complex 3d or its η ,η -
isomer (vide infra).
When the electrophilic attack takes place at the
terminal-substituted allyl moiety, two different products
can be formed (20a and 20b) unless the terminal sub-
stituents are identical (entries 1-2 and 8-9). The
subsequent nucleophilic attack on 20a and 20b gives 21a
and 21b, respectively, along with regeneration of Pd(0).
On the other hand, an incipient electrophilic attack at
the central or nonsubstituted allyl moiety of 3d (or its
1
3
η ,η -isomer) affords 22, which can undergo nucleophilic
attack at the more or at the less substituted allylic
terminus providing 23a and 23b. Accordingly, when the
two terminal substituents of 3d are different (entries 3-6
and 10-13), a total of four different regioisomers (21a ,b
and 23a ,b) can be formed. Even with identical terminal
substituents (entries 1-2 and 8-9), two different regioi-
somers are expected. However, in the reactions described
by eq 8 only a single regioisomer corresponding to 23a
is formed. This isomer can only be formed by an exclusive
attack at the central or nonsubstituted allylic moiety of
3
d followed by a nucleophilic attack at 22.
Formation of 23a alone also involves a highly regiose-
lective nucleophilic attack on 22. The high level of
regiochemistry of the nucleophilic attack on similar types
of (mono-)allylpalladium intermediates has been studied
by Keinan and Sahai.17 These authors found that mal-
onate type nucleophiles attack the less substituted allylic
1
7
moiety with a remarkably high regioselectivity.
A
nucleophilic attack by a bulky malonate congener at the
methyl-substituted allylic terminus in 22 provides 23a ,
1
7
in line with the findings of Keinan and Sahai.
The most interesting feature of the above-discussed
reactions (eqs 6-8) is certainly the dependence of the
regiochemistry of the incipient electrophilic attack on the
substituent pattern of the substrates. In the presence of
two terminal substituents on one of the allyl moieties in
the unsymmetrical bis-allylpalladium intermediate, as
in 3d , a very high regioselectivity occurs (eq 8); however
when the intermediate is mono-alkyl substituted (Scheme
3
, eqs 6-7), the regioselectivity is poor and, in addition,
homo-coupling readily takes place.
A possible explanation for the formation of homo-
coupled products is the exchange of the allyl groups
between the (mono-)allylpalladium (19) and bisallylpal-
ladium species (3d ). This process has been studied by
Yamamoto and co-workers15 using the dynamic NMR
technique. In such a process, an unsymmetrical bis-
allylpalladium complex (3c) can be converted to a sym-
metrical one (3a ), giving a homo-coupling product (5).
Fortunately, this processes is suppressed by using allyl
a
Reaction conditions: 5 mol % of Pd(PPh3)4, 1a ,b, 2d -i, and 4
b
in CH2Cl2 at 40 °C for 3 h. Isolated yield.
homo-coupled product can easily be removed by chroma-
tography, and the relatively good yields are still main-
tained. It is also important to note that the above
(17) Keinan, E.; Sahai, M. J . Chem. Soc., Chem. Commun. 1984,
648.

Regioselective Control of Bis-allylpalladium Intermediates
Sch em e 4
J . Org. Chem., Vol. 66, No. 5, 2001 1689
chlorides 2d -i in the three-component coupling reac-
tions. One possible explanation is that the exchange of a
terminal-substituted allylic moiety in 3d is slower than
the electrophilic attack of this complex.
out using a double-ú(DZ)+P basis constructed from the
LANL2DZ basis2
0-22
by adding one set of d-polarization
functions to the heavy atoms (exponents: C, 0.63; N,
0.864, P, 0.34) and one set of diffuse d-functions for
palladium (exponent: 0.0628). Harmonic frequencies
have been calculated at the level of optimization for all
structures to characterize the calculated stationary points
and to determine the zero-point energies (ZPE). Fully
optimized transition state structures 27a , 28a , and 29a
have been characterized by a single imaginary frequency,
while the rest of the fully optimized structures possess
only real frequencies. All calculations have been con-
Th eor etica l Stu d ies
We have carried out DFT calculations (Figures 1 and
2
) with the aim of examining the electronic and steric
effects of the alkyl substituents on the regiochemistry of
the electrophilic attack in the three-component coupling
reactions discussed above. In a recent theoretical study16
it was shown that the electrophilic attack proceeds
23
ducted by employing the Gaussian 98 program package.
1
3
through the η ,η -form of the bis-allylpalladium com-
The theoretical studies involve an investigation the
electrophilic attack on the parent (25) and on 1,3-
dimethyl-substituted (26a and 26b) bis-allylpalladium
complexes. Reactant 4 is modeled by acrylonitrile (AN)
1
plexes and that the electrophilic attack on the η -allyl
moiety of these complexes (eq 9) occurs with a remark-
ably low activation energy.
and the PPh
3 3
ligand is replaced by PH to reduce the
computational burden of the study.
(
19) Perdew, J . P.; Wang, Y. Phys. Rev. B 1992, 45, 13244.
(20) Dunning, T. H.; Hay, P. J . Modern Theoretical Chemistry;
Plenum: New York, 1977; Vol. 3; p 1.
(21) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 270.
(22) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 299.
(23) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J . R.; Zakrzewski, V. G.; Montgomery, J . A.;
Stratmann, R. E.; Burant, J . C.; Dapprich, S.; Millam, J . M.; Daniels,
A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J .; Barone, V.;
Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford,
S.; Ochterski, J .; Petersson, G. A.; Ayala, P. Y.; Q. Cui; Morokuma,
K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J . B.;
Cioslowski, J .; Ortiz, J . V.; Stefanov, B. B.; G. Liu; Liashenko, A.;
Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.; Fox, D. J .; Keith,
T.; Al-Laham, M. A.; Peng, C. Y.; A. Nanayakkara; Gonzalez, C.;
Challacombe, M.; Gill, P. M. W.; J ohnson, B.; W. Chen; Wong, M. W.;
Andres, J . L.; Gonzalez, C.; M. Head-Gordon; Replogle, E. S.; Pople, J .
A. Gaussian 98; Gaussian, Inc.: Pittsburgh, PA, 1998.
Com p u ta tion a l Meth od s. All geometries were fully
optimized by employing a Becke-type18 three-parameter
density functional model, B3PW91. This so-called hybrid
functional includes the exact (Hartree-Fock) exchange,
the gradient-corrected exchange functional introduced by
Becke,18 and the more recent correlation functional of
1
9
Perdew and Wang. All calculations have been carried
(18) Becke, A. D. J . Chem. Phys. 1993, 98, 5648.

1
690 J . Org. Chem., Vol. 66, No. 5, 2001
Solin et al.
F igu r e 1. Selected B3PW91/LANL2DZ+P geometrical parameters for bis-allylpalladium complexes, TS structures, and products
of the electrophilic attack by acrylonitrile (bond lengths in Å, energies in kcal/mol). The zero-point vibration corrected energies
are given in italics. The numberation of the allyl moieties is given in Scheme 1.
1
3
1
3
3
St a b ilit y of t h e η ,η -b is-Allylp a lla d iu m Com -
p lexes. In the presence of π-acceptor ligands (such as
tion state (η or η ) of the allyl moiety. The η -dimethyl-
substituted complex (26b) is more stable by 3 kcal/mol
3
3
1
PH
3
), the η ,η -bis-allylpalladium complexes (3a and 24)
are converted to the corresponding η ,η -forms (25, 26a ,
and 26b) in an exothermic reaction. From an unsym-
metrical η ,η -complex, such as 24, at least two different
η ,η -bis-allylpalladium complexes can be formed, 26a
and 26b. The effects of the allylic methyl substituents
than its η -dimethyl-substituted counterpart (26a ). In-
1
3
terestingly, the formation of 26b (-19.6 kcal/mol) is about
as exothermic as the formation of the unsubstituted
complex 25 (-19.2 kcal/mol), also suggesting that the
energy difference between 26a and 26b cannot be ex-
plained only by the steric effects of the methyl substit-
uents.
3
3
1
3
1
3
on the stability of the η ,η -forms depend on the coordina-

Regioselective Control of Bis-allylpalladium Intermediates
J . Org. Chem., Vol. 66, No. 5, 2001 1691
micity (-24-25 kcal/mol) the electrophilic attack is an
irreversible step. In the product complexes the cyano-
1
hexenyl moiety is η -coordinated to palladium. This
cyanohexenyl moiety is also a potential nucleophile,
3
which can subsequently attack the η -allyl moiety of the
complex.
Relevan ce of th e Th eor etical Resu lts in th e Ch em -
istr y of Bis-a llylp a lla d iu m Com p lexes. Formation of
3
3
an unsymmetrical η ,η -bis-allylpalladium intermediate
in the palladium-catalyzed three-component coupling
reactions involves the fact that electrophilic and subse-
quent nucleophilic attack can afford up to four isomeric
3
3
products (Scheme 4). The η ,η -bis-allylpalladium inter-
1
3
mediate is converted to various η ,η -form isomers in the
presence of π-acceptor ligands. The above theoretical
calculations clearly indicate that the electronic effects of
1
3
the alkyl substituents on the stability of the η ,η
F igu r e 2. Energy profiles for the reaction of bis-allylpalla-
dium complexes 3a and 24 with acrylonitrile (AN) in the
presence of the PH ligand. All energies are given in kcal/mol.
3
complexes depend on the coordination state of the
substituted allyl moiety: An alkyl substituent at the
metalated terminal carbon (C4 in 26a ) destabilizes the
complex. Furthermore, an alkyl substituent decreases the
nucleophilicity of the attacked carbon (C6 in 26a ), and
therefore the activation barrier to the electrophilic attack
The methyl carbons are close to palladium in both 26a
and 26b. In 26a the Pd-C(C4) distance (3.07 Å) is
shorter (see Scheme 1 for numberation of the allyl moiety)
than the corresponding distance in 26b (Pd-C(C1) ) 3.25
Å, and Pd-C(C3) ) 3.43 Å). However, in 26b both methyl
groups are involved in repulsive interactions with pal-
ladium, while in 26a the C6 methyl substituent is far
away from the central atom. It can, therefore, be assumed
that the steric effects of the methyl group(s) destabilizes
1
is higher for a terminally alkylated η -moiety (28a ) than
for an unsubstituted one (29a ). Accordingly, with an
appropriate choice of the substituent pattern, the regi-
oselectivity of the electrophilic attack can be fully con-
trolled.
A substituent pattern providing a high level of regi-
oselectivity in the electrophilic attack requires terminal
alkyl substituents at one of the allyl moieties in the bis-
allylpalladium intermediate and unsubstituted terminal
carbons at the other (cf. 3d ). This substituent pattern
guarantees that the introductory electrophilic attack
occurs at the unsubstituted allyl moiety. The different
bulk of the alkyl substituents helps to control even the
regiochemistry of the nuclephilic attack.17 If one is to
employ terminal substituents other than alkyl groups,
2
6a and 26b to a similar extent. On the other hand, the
electronic effects of the methyl substituents in 26a and
6b are basically different. An important destabilizing
2
factor in 26a is an electronic interaction between the
filled σ(Pd-C4) and the pseudo-πCH3 MOs. This is a four-
electron interaction, which is closely related to the n-πCH3
3
interaction destabilizing sp alkyl anions, such as the
ethyl anion.24 Terminal methyl substituents on the η3-
coordinated allyl (26b) do not experience this destabiliz-
1
3
1
3
the substituent effects on the stability of the various η ,η -
bis-allylpalladium intermediates will have to be carefully
analyzed. Such an analysis can easily be done using the
above theoretical model.
ing interaction, leading to a more stable η ,η -bis-
allylpalladium complex.
Electr op h ilic Atta ck by Acr ylon itr ile. The electro-
philic attack on 25 and 26a ,b proceeds through TS
structures 27a , 28a , and 29a , respectively (Figure 2). The
activation energy of the electrophilic attack on the
unsubstituted complex 25 (14.2 kcal/mol) is somewhat
Con clu d in g Rem a r k s
In this study we have shown that the three-component
coupling reactions of allylstannanes 1a ,b, allyl chlorides
d -i, and benzylidenemalonitrile proceed with excellent
regiochemistry and with good yields. The theoretical
calculations indicate that the high regioselectivity can
be ascribed to the electronic effects of the alkyl substit-
uents. The terminal alkyl substituents in the bis-allylpal-
ladium intermediate of the reaction have two important
effects: destabilization of the η ,η -bis-allylpalladium
intermediate when the η -moiety is substituted and an
3
higher than that of the η -methyl-substituted complex
2
6b (12.9 kcal/mol). However, the activation barrier to
2
1
the electrophilic attack on the η -methyl-substituted
complex 26a is considerably higher (by 2.9 kcal/mol) than
the activation barrier to the reaction for its η -methyl-
3
substituted counterpart 26b. This clearly indicates that
the methyl-substituted carbon (C6) in 26a is much less
nucleophilic than the unsubstituted terminal carbon in
1
3
2
5 and 26b. This reactivity feature and the higher
1
thermodynamic stability of 26b work in the same direc-
tion and make the 24 f 26b f 29a f29b pathway more
favorable than the competing 24 f 26a f 28a f28b
pathway. Thus, the electrophilic attack on an unsym-
metrically substituted bis-allylpalladium (24) takes place
at the unsubstituted allyl moiety in complete agreement
with our experimental findings (Scheme 4, Table 1).
Formation of the reaction products 27b, 28b, and 29b
is an exothermic process. Because of the high exother-
increase in the activation barrier of the electrophilic
attack brought about by the alkyl substitution.
Exp er im en ta l Section
The starting materials were purchased from Aldrich or
Lancaster. The alkylallyl chlorides and 2-methylallyltributyl-
2
5-29
tin were prepared using standard literature procedures.
(
25) Brooks, L. A.; Snyder, H. R. Organic Syntheses; Wiley: New
York, 1955; Collect. Vol. III, p 698.
(26) Magid, R. M.; Fruchey, O. S.; J ohnson, W. L.; Allen, T. G. J .
Org. Chem. 1979, 44, 359.
(
24) Albright, T. A.; Burdett, J . K.; Whangbo, M.-H. Orbital Interac-
tions in Chemistry; Wiley: New York, 1985; p 152.

1
692 J . Org. Chem., Vol. 66, No. 5, 2001
Solin et al.
Thesolvents were freshly distilled prior to use. All reactions
were conducted under an argon atmosphere by employing
5,5-Dicya n o-8-cycloh exyl-6-m et h yl-4-p h en yloct a -1,7-
d ien e (10). H NMR: δ 7.35 (m, 5H), 5.44 (m, 1H), 5.37 (m,
1
1
13
standard manifold techniques. The H and C NMR spectra
were recorded in CDCl solutions at 300 and 75 MHz,
respectively, at room temperature. The chemical shifts (ppm)
are obtained using CDCl as an internal standard (7.26 ppm,
2H), 5.02 (dd, J ) 17.2 and 1.2 Hz, 1H), 4.93 (dd, J ) 9.6 and
1.2 Hz, 1H), 3.05 (dd, J ) 11.7 and 4.2 Hz, 1H), 2.88 (m, 2H),
2.33 (m, 1H), 2.04-1.97 (br m, 1H) 1.81-1.65 (br m, 5H), 1.31
(d, J ) 6.9 Hz, 3H), 1.40-1.05 (m, 5H). 13C NMR: δ 143.2,
135.5, 133.9, 129.5, 129.0, 128.9, 123.7, 118.5, 115.1, 115.1,
49.9, 48.8, 42.0, 41.3, 37.9, 33.2, 33.1, 26.4, 26.3, 19.1. MS
3
3
1
13
H; 77.36 ppm, C). Merck silica gel 60 (230-400 mesh) was
used for the chromatography.
+
Gen er a l P r oced u r e. A mixture of the corresponding allyl
chloride (0.38 mmol), benzylidenemalonitrile (0.32 mmol), and
(EI): m/z (rel intensity) 332 (M , 3), 131 (64), 81 (100), 77 (6).
1
H NMR: δ 7.38 (m, 5H), 5.64 (dd, J ) 15.3 and 9.2 Hz, 1H),
Pd(PPh
3
)
4
(0.016 mmol, 5 mol %) in dichloromethane (1 mL)
5.50-5.30 (br m, 2H), 5.02 (dd, J ) 17.1 and 1.8 Hz, 1H) 4.95
(dd, J ) 10.2 and 1.8 Hz, 1H), 3.10 (dd, J ) 9.3 and 6.3 Hz,
1H), 2.76 (m, 2H), 2.55 (m, 1H), 2.10-1.95 (br m, 1H) 1.80-
1.60 (br m, 5H), 1.34 (d, J ) 6.6 Hz, 3H), 1.40-1.05 (m, 5H).
was stirred for 15 min at room temperature. Then, allylstan-
nane (0.38 mmol) was added, and the reaction mixture was
stirred for 3 h at 40 °C. The reaction mixture was diluted with
ether (5 mL) and treated with a saturated KF solution. After
filtration, the organic phase was washed with water and brine,
1
3
C NMR: δ 142.9, 136.3, 133.9, 129.2, 129.2, 129.0, 124.5,
118.5, 115.2, 114.3, 49.6, 49.4, 42.5, 41.1, 35.8, 33.2, 33.2, 26.4,
+
dried over MgSO
4
, and concentrated. The products were
26.3, 17.5. MS (EI): m/z (rel intensity) 332 (M , 2), 131 (60),
isolated by silica gel chromatography using a pentane-ether
eluent. The two diastereomers formed could usually be sepa-
rated by chromatography (the exceptions were 8 and 14) so
the NMR data of the diastereomeric forms is given separately.
81 (100), 77 (7).
5,5-Dicya n o-6-m eth yl-4,9-d ip h en yln on a -1,7-d ien e (11).
H NMR: δ 7.27 (m, 10H), 5.51 (m, 3H), 4.98 (m, 2H), 3.42 (d,
J ) 6.6 Hz, 2H), 3.02 (dd, J ) 11.6 and 4.4 Hz, 1H), 2.87 (m,
1
1
3
4
,4-Dicya n o-2,7-d im et h yl-5-p h en yloct a -1,7-d ien e (6).
H NMR: δ 7.38 (m, 5H), 5.12 (m, 1H), 5.03 (m, 1H), 4.70 (br
s, 1H), 4.63 (br s, 1H), 3.24 (dd, J ) 10.0 and 5.2 Hz, 1H), 2.90
2H), 2.40 (m, 1H), 1.36 (dd, J ) 6.8 and 1.1 Hz, 3H). C NMR:
139.6, 136.1, 135.4, 133.8, 129.4, 129.0, 128.9, 128.8, 128.7,
127.2, 126.7, 118.5, 115.1, 115.0, 50.0, 48.7, 41.8, 39.6, 38.0,
18.8. 1H NMR: δ 7.37 (m, 5H), 7.27 (m, 5H), 5.84 (m, 1H),
5.56 (m, 1H), 5.39 (m, 1H), 4.96 (dd, J ) 17.1 and 1.5 Hz, 1H),
4.91 (dd, J ) 10.2 and 1.5 Hz, 1H), 3.44 (d, J ) 6.9 Hz, 2H),
3.10 (dd, J ) 9.6 and 6.0 Hz, 1H), 2.78 (m, 2H), 2.60 (m, 1H),
1.37 (d, J ) 6.9 Hz, 3H). C NMR: δ 139.6, 136.1, 135.5, 133.7,
129.3, 129.1, 129.0, 128.9, 128.7, 128.4, 126.6, 118.6, 115.0,
114.3, 49.4, 49.4, 42.3, 39.3, 36.0, 17.2. Anal. Calcd for
1
(
m, 2H), 2.48 (d, J ) 14.0 Hz, 1H), 2.25 (d, J ) 14.0 Hz, 1H),
1
1
4
2
.90 (s, 3H), 1.62 (s, 3H). 13C NMR: δ 140.7, 137.8, 135.6,
29.4, 129.3, 129.2, 118.7, 116.1, 115.2, 114.9, 51.6, 44.5, 42.9,
0.3, 23.4, 22.5. MS (EI): m/z (rel intensity) 265 (M+ + 1, 10),
49 (17), 145 (100), 117 (60), 77 (6).
1
3
5
,5-Dicya n o-6-m eth yl-4-p h en yln on a -1,7-d ien e (7). 1
H
NMR: δ 7.35 (m, 5H), 5.45 (m, 3H), 5.03 (dd, J ) 16.8 and 1.5
Hz, 1H), 4.94 (dd, J ) 9.9 and 1.8 Hz, 1H), 3.08 (dd, J ) 11.7
and 4.5 Hz, 1H), 2.86 (m, 2H), 2.37 (m, 1H), 1.76 (d, J ) 4.8
24 24 2
C H N : C, 84.67; H, 7.11; N, 8.23. Found: C, 84.58; H, 7.26;
N, 8.23.
1
3
Hz, 3H), 1.31 (d, J ) 6.9 Hz, 3H). C NMR: δ 135.5, 133.9,
7,7-Dicyan o-6-m eth yl-8-ph en ylu n deca-1,4,10-tr ien e (12).
H NMR: δ 7.35 (m, 5H), 5.82 (m, 1H), 5.45 (m, 3H), 5.09 (m,
1
1
4
5
9
32.1, 129.4, 129.0, 128.9, 127.4, 118.5, 115.1, 115.0, 49.8, 49.8,
1.9, 37.8, 18.8, 18.5.; H NMR: δ 7.39 (m, 5H), 5.70 (m, 1H),
.47 (m, 2H), 5.03 (dd, J ) 17.2 and 2.0 Hz, 1H), 4.95 (dd, J )
.6 and 2.0 Hz, 1H), 3.11 (dd, J ) 9.2 and 6.0 Hz, 1H), 2.80
1
2H), 5.03 (dd, J ) 17.0 and 1.4 Hz, 1H), 4.94 (dd, J ) 10.2
and 1.1 Hz, 1H), 3.07 (dd, J ) 11.6 and 4.1 Hz, 1H), 2.87 (m,
4H), 2.41 (m, 1H), 1.34 (d, J ) 6.9 Hz, 3H). 13C NMR: 135.8,
135.4, 134.8, 133.8, 129.5, 129.0, 128.9, 127.2, 118.5, 116.5,
(m, 2H), 2.55 (m, 1H), 1.76 (dd, J ) 6.4 and 1.6 Hz, 3H), 1.34
13
1
(d, 6.8 Hz, 3H). C NMR: δ 136.3, 134.0, 131.7, 129.3, 129.2,
115.1, 114.9, 49.9, 48.7, 41.9, 37.8, 37.1, 18.9. H NMR: δ 7.38
1
1
29.0, 128.3, 118.5, 115.2, 114.5, 49.4, 49.3, 42.3, 36.0, 18.3,
7.1. Anal. Calcd for C18 : C, 81.78; H, 7.63; N, 10.60.
(m, 5H), 5.70 (m, 2H), 5.45 (m, 2H), 4.98 (m, 4H), 3.10 (dd, J
) 9.6 and 6.0 Hz, 1H), 2.80 (m, 4H), 2.54 (m, 1H), 1.36 (d, J )
6.6 Hz, 3H). 13C NMR: δ 136.1, 135.8, 134.3, 133.8, 129.2,
129.1, 129.0, 128.2, 118.5, 116.4, 115.0, 114.3, 49.4, 49.3, 42.3,
20 2
H N
Found: C, 81.79; H, 7.80; N, 10.45.
-(Cycloh ex-2-en yl)-5,5-dicyan o-4-ph en ylpen t-1-en e (8).
H NMR: δ 7.38 (m, 10H), 6.11-6.04 (br m, 2H), 5.75 (m, 2H),
.51 (m, 2H), 5.07 (m, 2H), 4.97 (m, 2H), 3.31 (dd, J ) 10.4
and 5.2 Hz, 1H), 3.20 (dd, J ) 10.8 and 4.8 Hz, 1H), 2.91 (m,
H), 2.42-2.40 (br m, 2H), 2.15-2.06 (br m, 6H), 1.91-1.89
br m, 2H), 1.72-1.55(br m, 2H), 1.50-1.40 (br m, 2H). 13
NMR: δ 135.6, 135.6, 134.7, 134.2, 133.9, 133.9, 129.4, 129.3,
5
1
36.8, 36.1, 17.2. Anal. Calcd for C20
22 2
H N : C, 82.72; H, 7.64;
5
N, 9.65. Found: C, 82.56; H, 7.53; N, 9.79.
5,5-Dicya n o-2,6-d im eth yl-4-p h en yln on a -1,7-d ien e (13).
H NMR: δ 7.34 (m, 5H), 5.47 (m, 2H), 4.66 (s, 1H), 4.56 (s,
1
4
(
C
1H), 3.21 (dd, J ) 10.8 and 4.4 Hz, 1H), 2.83 (m, 2H), 2.38 (m,
1H), 1.77 (d, J ) 4.9 Hz, 3H), 1.57 (s, 3H) 1.32 (d, J ) 6.9 Hz,
3H). 13C NMR: δ 140.9, 135.8, 132.2, 129.5, 128.9, 127.5, 115.3,
115.1, 114.9, 49.0, 48.4, 41.9, 41.6, 22.5, 18.7, 18.4. MS (EI):
1
1
2
29.3, 129.1, 129.0, 129.0, 123.8, 122.1, 118.6, 115.3, 115.2,
15.0, 114.4, 48.8, 48.8, 48.7, 48.5, 40.3, 39.9, 37.5, 36.6, 26.6,
5.0, 25.0, 24.9, 21.3, 21.3. MS (EI): m/z (rel intensity) 277
+
m/z (rel intensity) 279 (M + 1, 11), 263 (20), 145 (100), 117
+
1
(M
+ 1, 10), 131 (100), 81 (39), 77 (5).
(49), 77 (2). H NMR: δ 7.37 (m, 5H), 5.72 (m, 1H), 5.49 (m,
5
,5-Dicya n o-6,9-d im et h yl-4-p h en yld eca -1,7-d ien e (9).
1H), 4.67 (m, 1H), 4.58 (s, 1H), 3.24 (dd, J ) 11.2 and 4.4 Hz,
1H), 2.74 (m, 2H), 2.58 (m, 1H), 1.77 (dd, J ) 6.8 and 1.6 Hz,
3H), 1.55 (s, 3H), 1.35 (d, 7.2 Hz, 3H). 13C NMR: δ 140.8, 136.5,
131.7, 129.2, 129.1, 129.0, 128.3, 115.3, 115.0, 114.5, 49.5, 47.9,
42.5, 39.5, 22.4, 18.3, 17.4. MS (EI): m/z (rel intensity) 279
1
H NMR: δ 7.35 (m, 5H), 5.40 (m, 3H), 5.03 (dd, J ) 17.1 and
1
1
6
3
1
.5 Hz, 1H), 4.94 (dd, J ) 10.2 and 1.8 Hz, 1H), 3.05 (dd, J )
1.4 and 4.2 Hz, 1H), 2.88 (m, 2H), 2.34 (m, 2H), 1.32 (d, J )
.6 Hz, 3H), 1.06 (d, J ) 6.9 Hz, 3H), 1.01 (d, J ) 6.9 Hz,
1
3
+
H). C NMR: δ 144.3, 135.5, 133.9, 129.5, 129.0, 128.9, 123.3,
(M + 1, 2), 263 (17), 145 (100), 117 (51), 77 (3).
18.5, 115.1, 115.1, 49.9, 48.8, 41.9, 37.9, 31.8, 22.7, 22.5, 19.1.
5,5-Dicyan o-5-(cycloh ex-2-en yl)-2-m eth yl-4-ph en ylpen t-
+
1
MS (EI): m/z (rel intens) 292 (M , 2), 277 (6), 251 (5), 131
1-en e (14). H NMR: δ 7.36 (m, 10H), 6.11-6.06 (br m, 2H),
1
(
(
100), 91 (34), 77 (2), 69 (14). H NMR: δ 7.38 (m, 5H), 5.65
5.78-5.72 (br m, 2H), 4.69 (s, 2H), 4.62 (s, 1H), 4.59 (s, 1H),
3.43 (dd, J ) 10.5 and 4.5 Hz, 1H), 3.33 (dd, J ) 9.3 and 5.7
Hz, 1H), 2.85 (m, 4H), 2.43-2.37 (br m, 2H), 2.13-2.04 (br m,
6H), 1.94-1.87 (br m, 2H), 1.61 (s, 3H), 1.60 (s, 3H), 1.70-
1.54 (br m, 2H), 1.49-1.43 (br m, 2H). 13C NMR: δ 140.7,
135.7, 135.7, 134.7, 134.2, 129.2, 129.1, 129.0, 128.9, 128.9,
123.7, 122.1, 115.4, 115.2, 115.1, 114.9, 114.8, 114.5, 49.2, 47.4,
47.3, 41.5, 40.6, 40.5, 40.1, 26.8, 25.2, 25.0, 22.7, 22.6, 21.5,
dd, J ) 15.6 and 6.9 Hz, 1H), 5.44 (m, 2H), 5.02 (dd, J ) 17.1
and 1.8 Hz, 1H), 4.94 (dd, J ) 10.2 and 1.8 Hz, 1H), 3.10 (dd,
J ) 9.3 and 6.0 Hz, 1H), 2.79 (m, 2H), 2.53 (m, 1H), 2.35 (m,
1
H), 1.34 (d, J ) 6.9 Hz, 3H), 1.03 (d, J ) 6.9 Hz, 3H), 1.01 (d,
13
J ) 6.9 Hz, 3H). C NMR: δ 144.1, 136.2, 133.9, 129.2, 129.1,
1
2
29.0, 124.1, 118.5, 115.1, 114.3, 49.5, 49.4, 42.3, 35.9, 31.6,
+
2.7, 22.7, 17.4. MS (EI): m/z (rel intensity) 292 (M , 3), 277
(7), 251 (7), 131 (100), 91 (19), 77 (2), 69 (4).
21.4. Anal. Calcd for C20
Found: C, 82.54; H, 7.76; N, 9.60.
, 5-Dicyan o-2,6,9-tr im eth yl-4-ph en yldeca-1,7-dien e (15).
H NMR: δ 7.34 (m, 5H), 5.39 (m, 2H), 4.65 (m, 1H), 4.55 (m,
1H), 3.20 (dd, J ) 11.2 and 4.1 Hz, 1H), 2.82 (m, 2H), 2.35 (m,
22 2
H N : C, 82.72; H, 7.64; N, 9.65.
5
(
(
(
27) Renaud, P.; Fox, M. A. J . Org. Chem. 1988, 53, 3754.
28) Still, W. C. J . Am. Chem. Soc. 1976, 100, 1481.
29) Mori, K.; Waku, M.; Sakakibara, M. Tetrahedron 1985, 41, 2825.
1

Regioselective Control of Bis-allylpalladium Intermediates
J . Org. Chem., Vol. 66, No. 5, 2001 1693
2
3
1
3
H), 1.57 (s, 3H) 1.32 (d, J ) 6.9 Hz, 3H), 1.07 (d, J ) 6.8 Hz,
H), 1.02 (d, J ) 6.8 Hz, 3H). 13C NMR:144.4, 140.7, 135.6,
29.5, 128.8, 123.4, 115.2, 115.1, 114.8, 49.1, 48.5, 42.0, 41.8,
1.8, 22.8, 22.6, 22.6, 19.1. MS (EI): m/z (rel intensity) 306
5H), 5.86 (m, 1H), 5.56 (m, 1H), 4.63 (s, 1H), 4.53 (s, 1H), 3.44
(d, 6.9 Hz, 2H), 3.23 (dd, J ) 11.0 and 4.3 Hz, 1H), 2.64 (m,
3H), 1.45 (s, 3H), 1.38 (d, 6.6 Hz, 3H). 13C NMR: δ 140.6, 139.5,
136.3, 135.7, 129.1, 128.9, 128.9, 128.8, 128.3, 126.7, 115.1,
114.9, 114.3, 49.6, 47.8, 42.3, 39.6, 39.4, 22.5, 17.5. MS (EI):
+
1
(M , 3), 291 (10), 263 (49), 145 (100), 117 (69), 69 (16).
H
+
NMR: δ 7.37 (m, 5H), 5.67 (dd, J ) 15.4 and 6.9 Hz, 1H), 5.40
m/z (rel intensity) 354 (M , 4), 263 (16), 145 (100), 117 (39),
91 (13).
(
1
1
ddd, J ) 15.4 and 9.3 and 1.4 Hz, 1H), 4.66 (m, 1H), 4.59 (s,
H), 3.25 (dd, J ) 11.2 and 4.1 Hz, 1H), 2.77 (m, 2H), 2.57 (m,
H), 2.36 (m, 1H), 1.56 (s, 3H), 1.36 (d, J ) 6.6 Hz, 3H), 1.04
7,7-Dicya n o-6,10-d im e t h yl-8-p h e n ylu n d e ca -1,4,10-
1
tr ien e (18). H NMR: δ 7.34 (m, 5H), 5.83 (m, 1H), 5.50 (m,
1
3
(
1
1
d, J ) 6.8 Hz, 3H), 1.02 (d, J ) 6.8 Hz, 3H). C NMR: δ
2H), 5.10 (m, 2H), 4.66 (m, 1H), 4.56 (m, 1H), 3.20 (dd, J )
44.2, 140.8, 136.6, 129.2, 129.2, 129.0, 124.3, 115.3, 115.0,
10.8 and 4.8 Hz, 1H), 2.84 (m, 4H), 2.41 (m, 1H), 1.57 (s, 3H),
1
3
14.4, 49.7, 47.8, 42.3, 39.4, 31.6, 22.6, 22.6, 22.5, 17.6. MS
1.35 (d, J ) 6.9 Hz, 3H). C NMR: δ 140.6, 135.8, 135.5, 134.8,
+
(EI): m/z (rel intensity) 306 (M , 3), 291 (10), 263 (15), 145
129.4, 128.8, 127.3, 116.4, 115.1, 114.9, 114.7, 48.9, 48.4, 41.9,
+
(100), 117 (37), 69 (15).
41.6, 37.0, 22.5, 18.8. MS (EI): m/z (rel intensity) 305 (M
+
1
5
,5-Dicya n o-8-cycloh exyl-2,6-d im et h yl-4-p h en yloct a -
1, 1), 263 (41), 145 (100), 117 (45), 77 (7), 67 (50). H NMR: δ
7.37 (m, 5H), 5.81 (m, 1H), 5.78 (m,1H), 5.50 (m, 1H), 5.09
(dd, J ) 14.0 and 1.6 Hz, 1H), 5.06 (dd, J ) 7.2 and 1.6 Hz,
1H) 4.67 (m, 1H), 4.58 (s, 1H), 3.25 (dd, J ) 11.2 and 4.4 Hz,
1H), 2.84 (m, 2H), 2.75 (m, 2H), 2.59 (m, 1H), 1.56 (s, 3H),
1
1
,7-d ien e (16). H NMR: δ 7.33 (m, 5H), 5.39 (m, 2H), 4.65
(
s, 1H), 4.55 (s, 1H), 3.20 (dd, J ) 11.1 and 4.5 Hz, 1H), 2.82
(
5
m, 2H), 2.32 (m, 1H), 2.07-1.99 (br m, 1H) 1.79-1.67 (br m,
H), 1.57 (s, 3H) 1.32 (d, J ) 6.9 Hz, 3H), 1.40-1.05 (m, 5H).
C NMR: δ 143.4, 140.9, 135.7, 129.6, 128.9, 123.9, 115.3,
15.2, 114.8, 49.0, 48.4, 42.0, 41.7, 41.2, 33.2, 33.1, 26.3, 26.2,
1
3
13
1.36 (d, J ) 6.4 Hz, 3H). C NMR: δ 140.7, 136.4, 135.9, 134.5,
1
2
6
129.2, 129.0, 128.3, 116.6, 115.2, 115.0, 114.4, 49.5, 47.9, 42.3,
1
+
2.5, 19.0. H NMR: δ 7.36 (m, 5H), 5.65 (dd, J ) 15.4 and
39.6, 36.8, 22.5, 17.4. MS (EI): m/z (rel intensity) 305 (M
1, 1), 263 (10), 145 (100), 117 (47), 77 (5), 67 (37).
+
.8 Hz, 1H), 5.39 (ddd, J ) 15.4 and 9.1 and 1.1 Hz, 1H), 4.66
(d, J ) 0.8 Hz, 1H) 4.59 (s, 1H), 3.25 (dd, J ) 11.6 and 4.1 Hz,
Ack n ow led gm en t. This work was supported by the
Swedish Natural Science Research Council (NFR). The
calculations were done at the IBM SP2 parallel com-
puter facility of the Parallelldatorcentrum (PDC) at the
Royal Institute of Technology, Sweden. The authors
thank the PDC for a generous allotment of computer
time. The financial support of The Wenner-Gren Foun-
dations for a postdoctoral fellowship to S.N. is gratefully
acknowledged.
1
1
1
1
3
8
H), 2.73 (m, 2H), 2.58 (m, 1H), 2.07-1.98 (br m, 1H) 1.75-
.65 (br m, 5H), 1.55 (s, 3H),1.36 (d, J ) 6.6 Hz, 3H), 1.35-
1
3
.05 (m, 5H). C NMR: δ 143.0, 140.8, 136.6, 129.2, 129.1,
29.0, 124.7, 115.3, 115.0, 114.4, 49.7, 47.7, 42.4, 41.1, 39.3,
3.2, 33.1, 26.3, 26.2, 22.6, 17.7. Anal. Calcd for C24
3.19; H, 8.73; N, 8.08. Found: C, 83.01; H, 8.92; N, 8.07.
,5-Dicya n o-2,6-d im et h yl-4,9-d ip h en yln on a -1,7-d ien e
30 2
H N : C,
5
1
(
17). H NMR: δ 7.35-7.10 (br m, 10H), 5.62 (m, 1H), 5.51
(m, 1H), 4.63 (s, 1H), 4.51 (s, 1H), 3.42 (d, J ) 6.6 Hz, 2H),
3
1
1
1
2
1
.13 (dd, J ) 11.5 and 4.1 Hz, 1H), 2.79 (m, 2H), 2.37 (m, 1H),
.56 (d, J ) 6.8, 3H), 1.36 (d, J ) 6.6 Hz, 3H). 13C NMR: δ
40.7, 139.8, 136.4, 135.5, 129.4, 129.1, 128.9, 128.9, 128.8,
27.3, 126.8, 115.2, 115.1, 114.9, 48.9, 48.4, 41.9, 41.8, 39.5,
Su p p or tin g In for m a tion Ava ila ble: 13C NMR spectra for
compounds 6, 8-10, 13, 15, 17, and 18. This material is
available free of charge via the Internet at http://pubs.acs.org.
+
2.4, 18.7. MS (EI): m/z (rel intensity) 354 (M , 2), 263 (47),
1
45 (100), 117 (38), 91 (11). H NMR: δ 7.36 (m, 5H), 7.27 (m,
J O001374D