Aldehyde Addition and Copper-Mediated Allylation of Bicyclic Alkoxytitanacyclopentenes and -Pentadienes: New Selectivities and an Unusual Reaction

Article abstract of DOI:10.1021/ja982501e

Bicyclic titanacyclopentenes generated in situ from 1,6-enynes and (η²-propene)Ti(O-i-Pr)₂ (1) reacted with aldehydes at their alkenyl-titanium bond in the absence or presence of Ti(O-i-Pr)_nCl_4-n (n = 2 or 3) to give allyl alcohols such as 5-7 as a nearly single stereoisomer in good yields. Upon workup with DCl/D₂O or iodine, deuterio and iodo derivatives, 8 and 9, were obtained. Bicyclic titanacyclopentadienes prepared analogously from 1,6- or 1,7-diynes and 1 also reacted with aldehydes in the presence of an additional equivalent of Ti(O-i-Pr)₂Cl₂ to afford 1,2-dialkylidenecyclopentanes or -cyclohexanes having an alcohol moiety in their side chain in good yields. In place of the simple hydrolysis, deuteriolysis or iodinolysis gave the corresponding derivatives such as 21 or 22. Treatment of 1,6-enyne 10 with 1 in the standard way and then with a slight excess of i-PrMgCl at -50°C generated a new titanium species that, upon reaction with aldehydes, afforded unexpected adducts 34 and 41-45 virtually as a single isomer. Copper-mediated allylation of dialkoxytitanacyclopentene such as 3 with allyl bromide proceeded at their vinyl-titanium bond to give 48 and 50. Likewise, dialkoxytitanacyclopentadiene prepared from 29 and 1 underwent the regioselective copper-mediated monoallylation to give a 9:1 mixture of 53 and 54. Upon workup with deuteriochloric acid, the corresponding deuterated product was obtained with a high degree of deuterium incorporation.

Full text of DOI:10.1021/ja982501e

J. Am. Chem. Soc. 1999, 121, 1245-1255
1245
Aldehyde Addition and Copper-Mediated Allylation of Bicyclic
Alkoxytitanacyclopentenes and -Pentadienes: New Selectivities and
an Unusual Reaction
Hirokazu Urabe and Fumie Sato*
Contribution from the Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259
Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
ReceiVed July 15, 1998
Abstract: Bicyclic titanacyclopentenes generated in situ from 1,6-enynes and (η2-propene)Ti(O-i-Pr)2 (1) reacted
with aldehydes at their alkenyl-titanium bond in the absence or presence of Ti(O-i-Pr)nCl4-n (n ) 2 or 3) to
give allyl alcohols such as 5-7 as a nearly single stereoisomer in good yields. Upon workup with DCl/D2O
or iodine, deuterio and iodo derivatives, 8 and 9, were obtained. Bicyclic titanacyclopentadienes prepared
analogously from 1,6- or 1,7-diynes and 1 also reacted with aldehydes in the presence of an additional equivalent
of Ti(O-i-Pr)2Cl2 to afford 1,2-dialkylidenecyclopentanes or -cyclohexanes having an alcohol moiety in their
side chain in good yields. In place of the simple hydrolysis, deuteriolysis or iodinolysis gave the corresponding
derivatives such as 21 or 22. Treatment of 1,6-enyne 10 with 1 in the standard way and then with a slight
excess of i-PrMgCl at -50 °C generated a new titanium species that, upon reaction with aldehydes, afforded
unexpected adducts 34 and 41-45 virtually as a single isomer. Copper-mediated allylation of dialkoxytitana-
cyclopentene such as 3 with allyl bromide proceeded at their vinyl-titanium bond to give 48 and 50. Likewise,
dialkoxytitanacyclopentadiene prepared from 29 and 1 underwent the regioselective copper-mediated mono-
allylation to give a 9:1 mixture of 53 and 54. Upon workup with deuteriochloric acid, the corresponding
deuterated product was obtained with a high degree of deuterium incorporation.
Introduction
Almost all of the group 4 metallabicycles utilized in organic
synthesis have a bis(η5-cyclopentadienyl)titanium or -zirconium
moiety as the metal portion (Figure 1, MLm ) TiCp2 or ZrCp2).1
These compounds are readily available from the corresponding
bis-unsaturated compounds and a low-valent metal species and
undergo coupling reactions with a variety of electrophiles (El+)
to enable introduction of a carbon side chain and/or functional
groups.1 As the reactivities of metal complexes are often
considerably affected by the nature of their ligands, the same
type of metallacycles yet having ligands other than Cp may alter
their behavior in the above reactions, possibly leading to
development of new reactivity and selectivity.2 Alkoxy ligands
are a reasonable choice because group 4 metal alkoxides are
well-known and the alkoxide group is distinctive from the η5-
cyclopentadienyl group in terms of both electronic and steric
reasons. In conjunction with this discussion, a generation of
Figure 1.
allylation, emphasizing the unique feature observed for these
metallacycles.
Results and Discussion
Aldehyde Addition. When titanacyclopentene 3, generated
in situ from enyne 2 and (η2-propene)Ti(O-i-Pr)2 (1) in 90-
97% yield determined by hydrolysis and deuteriolysis,3a was
allowed to react with cyclohexanecarbaldehyde, allyl alcohol 5
was obtained in 7% yield as the coupling product (see eq 1).
The production of 5 was quite unexpected because the corre-
sponding Cp2-zirconacyclopentenes (Figure 1, B, MLm ) ZrCp2)
had been reported to react with aldehydes at their alkyl-
zirconium bond, not giving the allyl alcohols such as 5.1b,7
Gratifyingly, the low yield of 5 was soon improved by the
new titanabicycles having alkoxy ligands (Figure 1, MLm
)
Ti(O-i-Pr)2) has been recently reported.3-5 We would like to
report here the scope of their two fundamental reactions for
carbon-carbon bond formation, that is, aldehyde addition6 and
(3) (a) Urabe, H.; Hata, T.; Sato, F. Tetrahedron Lett. 1995, 36, 4261.
(b) Urabe, H.; Takeda, T.; Sato, F. Tetrahedron Lett. 1996, 37, 1253. (c)
Suzuki, K.; Urabe, H.; Sato, F. J. Am. Chem. Soc. 1996, 118, 8729. (d)
Urabe, H.; Suzuki, K.; Sato, F. J. Am. Chem. Soc. 1997, 119, 10014. (e)
Hideura, D.; Urabe, H.; Sato, F. Chem. Commun. 1998, 271.
(4) For a relevant review, see: Sato. F.; Urabe, H.; Okamoto, S. J. Synth.
Org. Chem. Jpn. 1998, 56, 424.
(5) For titanacycles having bulky aryloxy ligands, see: (a) Hill, J. E.;
Balaich, G.; Fanwick, P. E.; Rothwell, I. P. Organometallics 1993, 12, 2911.
(b) Thorn, M. G.; Hill, J. E.; Waratuke, S. A.; Johnson, E. S.; Fanwick, P.
E.; Rothwell, I. P. J. Am. Chem. Soc. 1997, 119, 8630.
(1) (a) Yasuda, H.; Nakamura, A. Angew. Chem., Int. Ed. Engl. 1987,
26, 723. (b) Buchwald, S. L.; Nielsen, R. B. Chem. ReV. 1988, 88, 1047.
(c) Negishi, E. In ComprehensiVe Organic Synthesis; Trost, B. M., Fleming,
I., Eds.; Pergamon Press: Oxford, 1991; Vol. 5, p 1163. (d) Broene, R. D.;
Buchwald, S. L. Science 1993, 261, 1696. (e) Negishi, E.; Takahashi, T.
Acc. Chem. Res. 1994, 27, 124. (f) Ohff, A.; Pulst, S.; Lefeber, C.; Peulecke,
N.; Arndt, P.; Burkalov, V. V.; Rosenthal, U. Synlett 1996, 111. (g) Sato,
F.; Urabe, H. In Handbook of Grignard Reagents; Silverman, G. S., Rakita,
P. E., Eds.; Marcel Dekker: New York, 1996; p 23.
(2) For the use of mono(cyclopentadienyl)zirconium trichloride in place
of bis(cyclopentadienyl) complexes in the diene cyclization, see: Nugent,
W. A.; Taber, D. F. J. Am. Chem. Soc. 1989, 111, 6435.
(6) A portion of this work has been communicated. Urabe, H.; Sato, F.
J. Org. Chem. 1996, 61, 6756.
10.1021/ja982501e CCC: $18.00 © 1999 American Chemical Society
Published on Web 01/29/1999

1246 J. Am. Chem. Soc., Vol. 121, No. 6, 1999
Urabe and Sato
Table 1. Cyclization of Enynes and Subsequent Reaction with
Aldehydesa
addition of an additive: if the aldehyde addition was performed
in the presence of an extra equivalent of Ti(O-i-Pr)2Cl2, the
desired product 5 was now obtained in 50% yield with very
high regio- and stereoselectivities (eq 1 and entries 3 and 4 in
Table 1). Other additives including TiCl(O-i-Pr)3, TiCl4, ZnCl2,
Me3SiCl, and BF3‚OEt2 proved to be less effective (around or
less than 30% yield of the product). Although the exact role of
the externally added titanium salt is unclear at present, it may
activate the aldehyde as a Lewis acid.8 Additional results are
summarized in Table 1. The reaction of titanabicycle 3 and an
aromatic aldehyde required TiCl(O-i-Pr)3 as the more preferable
additive than TiCl2(O-i-Pr)2 in order to afford the product in
good yield (entry 1). The stereochemistry of the tetra-substituted
double bond of the products was determined by NOE study of
1H NMR spectroscopy, and the relative stereochemistry of the
hydroxy and methyl groups will be discussed later. The presence
of the intermediate titanium species 4 in eq 1 was confirmed
by subsequent deuteriolysis or iodinolysis to give the corre-
sponding deuterated product 8 or the iodide 9 in good yields
(entries 5 and 6).
a See eq 1. b Isolated yields. Yields determined by 1H NMR
spectroscopy are shown in parentheses. c Diastereoselectivity. d Based
on aldehyde. e Product was isolated as a single isomer.
Figure 2.
Scheme 1
Titanacyclopentene 11 from enyne 10 having an alkyl group
rather than a trimethylsilyl group for the acetylenic substituent
no longer requires the assistance of the additive to undergo the
addition to aldehyde (Scheme 1). When enyne 10 was treated
with 1 followed by benzaldehyde at -50 °C for 2 h, the desired
product 13 was produced in 57% yield as an 85:15 mixture of
diastereoisomers, from which the pure major isomer was
separated in 41% yield by routine flash chromatography on silica
gel. Minimization of the steric hindrance around the reacting
position appears to be a critical factor for a smooth reaction in
the case of the titanacyclopentenes such as 11 (as compared to
3). To determine the 1,4-relative stereochemistry with respect
to the methyl and hydroxy groups of 13, we carried out
iodinolysis of the intermediate oxatitanacycle 12 to give the
corresponding iodide 14. Ring closure of 14 with KH in THF
took place to give bicyclic ether 15. The stereochemistry of 15
so far failed due to the instability of the iodinated adduct such
as 9. However, H NMR spectra of the authentic 13 and the
1
compounds 6 and 7 in question show the same tendency with
respect to the peak positions of the methyl proton and the allylic
proton R to the hydroxy group. Namely, both protons of the
major isomers always display an upfield shift as shown in the
experimental part. On the basis of these observations, the
structures of 6 and 7 and, hence, 5 are assigned parallel to that
of 13 by analogy.9
The stereochemical course of the addition would be well
explained by the least hindered approach of the aldehyde to
the reaction center from the convex face as illustrated above
(Figure 2), where the R′ group of an aldehyde is placed so as
not to suffer from the repulsion by the eclipsing R group of the
1
was unequivocally determined by H NMR analysis (coupling
constants and NOE enhancements as depicted), which, in turn,
confirmed the stereochemistry of the major isomer of 13 as
depicted.
The same technique to determine the relative stereochemistry
of the aforementioned silyl substituted adducts 5-7 (Table 1)
(7) Cope´ret, C.; Negishi, E.; Xi, Z.; Takahashi, T. Tetrahedron Lett. 1994,
35, 695.
(8) For reviews on organotitanium reagents, see: (a) Reetz, M. T.
Organotitanium Reagents in Organic Synthesis; Springer-Verlag: Berlin,
1986. (b) Ferreri, C.; Palumbo, G.; Caputo, R. In ComprehensiVe Organic
Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991;
Vol. 1, p 139. (c) Reetz, M. T. In Organometallics in Synthesis; Schlosser,
M., Ed.; Wiley: Chichester, 1994; p 195.
(9) Accordingly, our earlier (tentative) assignment to the stereochemistries
of 5-7 shown in ref 6 turned out to be wrong and should be revised.

Allylation of Bicyclic Titanacyclopentenes
J. Am. Chem. Soc., Vol. 121, No. 6, 1999 1247
Table 2. Cyclization of Diynes and Subsequent Reaction with
Scheme 2. Reaction of a Titanacyclopentadiene with
Aldehyde
Aldehydesa
titanacycle. This rationalization is consistent with the observation
that the bulkier the R group becomes (C6H13 f Me3Si), the
higher is the selectivity attained in the addition (R′ ) Ph, 85:
15 f >95:<5).
Two characteristic features should be noted for the above
reactions. The first is that the aldehyde addition proceeded
selectively at the alkenyl-metal bond rather than at the alkyl-
metal bond of the titanacycle, which is in marked contrast to
and complementary with the aforementioned reactions of Cp2-
zirconacyclopentenes1b,7 as shown in eq 2 (bold lines show the
newly formed carbon-carbon bond).
1
a See Scheme 2. b Isolated yields. Yields determined by H NMR
spectroscopy are shown in parentheses.
dialkylidenecyclopentane and -hexane frameworks. In addition,
a nitrogen heterocycle could be prepared as well (entry 8). The
addition of the titanacyclopentadienes to aldehydes always
proceeded at the carbon bearing a silyl group. The R-charge
stabilizing effect of a silyl group10 in the transition state to
increase the reactivity of the R3SiC-Ti bond toward aldehydes
would account for this regioselectivity. In the case of a diyne
having two different silyl groups such as Me3Si and (t-Bu)-
Me2Si (entry 3), the addition to an aldehyde took place at the
carbon bearing the less hindered trimethylsilyl group to yield
27, the regioisomer of which could not be isolated. Thus, from
the synthetic point of view, the appropriate choice of acetylenic
substituent may discriminate between the two acetylenic termini.
In the reaction with R-phenylpropionaldehyde, moderate dias-
tereoselectivity, approximately 3:1-4:1, was observed (entry
6).11 Like the reaction of the aforementioned titanacyclo-
pentenes, if an additional portion of TiCl2(O-i-Pr)2 was not
added prior to the aldehyde addition, the product yields
decreased by 10-30%.
The second point is that high 1,4-diastereoselectivity of the
resultant allyl alcohol, especially in the silylated series (>95:
<5 by 1H NMR analysis in comparison with an authentic
sample), could be attained.
Addition of metallacyclopentadienes to aldehydes is a related
reaction to give dienyl alcohol, but its viability as a synthetic
tool has not been pursued. This type of reaction with Cp2-
titanacyclopentadiene and its zirconium counterpart (Figure 1,
C, MLm ) TiCp2 or ZrCp2) has not appeared. One precedent
hitherto known is that a diaryloxytitanacyclopentadiene (Figure
1, C, MLm ) Ti[O(2,6-Ph2C6H3)]2) undergoes the addition to
benzophenone, but the generality of the reaction has not been
reported.5 The aforementioned finding of the preferred transfer
of the alkenyl-metal bond in the dialkoxytitanacyclopentenes
prompted us to investigate the addition of the titanacyclopen-
tadienes to aldehydes. Titanacyclopentadiene 17 generated from
the diyne 16 and 13a in >93% yield as estimated by protonolysis
(to give 18) reacted with an aldehyde in the presence of an
additional equivalent of TiCl2(O-i-Pr)2 to furnish the adduct 20
in a good yield after hydrolysis (Scheme 2). Virtually no trace
of another regioisomer formed, which proves that the reaction
was highly regioselective. The reaction should proceed through
the intermediate titanium species 19, the presence of which was
verified by its deuteriolysis and iodinolysis, to give the
corresponding products 21 and 22.
While the silylated diene moiety involved in the above
products is a useful synthetic intermediate as such,1,10,12,13 the
silyl group adjacent to the hydroxy group may be selectively
(10) (a) Weber, W. P. Silicon Reagents for Organic Synthesis; Springer-
Verlag: Berlin, 1983. (b) Colvin, E. W. Silicon in Organic Synthesis;
Butterworth: London, 1981.
(11) For the diastereoselectivity in the nucleophilic addition to chiral
aldehydes, see: (a) Heathcock, C. H. In Asymmetric Synthesis; Morrison,
J. D., Ed.; Academic Press: New York, 1984; Vol. 3, p 111. (b) Anh, N.
T. Top. Curr. Chem. 1980, 88, 145. (c) Seebach, D.; Weidmann, B.; Widler,
L. In Modern Synthetic Methods; Scheffold, R., Ed.; Otto Salle: Frankfurt
am Main, 1983; Vol. 3, p 217.
Various 1,6- and 1,7-diynes are suitable substrates for this
cyclization/aldehyde addition as shown in Table 2 to give 1,2-
(12) Nugent, W. A.; Calabrese, J. C. J. Am. Chem. Soc. 1984, 106, 6422.

1248 J. Am. Chem. Soc., Vol. 121, No. 6, 1999
Urabe and Sato
removed, if necessary, under basic conditions as exempli-
fied in eqs 3 and 4.14 From the synthetic point of view, this
Figure 3. Structural determination of 34.
considered as a dehydrogenated form of an isomer of 13! Its
structure was established by spectroscopic means and elemental
analysis.17 Moreover, the fine structure of the stereogenic centers
was deduced based on consideration of the coupling constants
and NOE experiments of H NMR spectroscopy as shown in
Figure 3.
1
conversion serves as a method to prepare E,Z-dialkylidenecy-
clopentanes and -hexanes, the synthesis of which is otherwise
a tedious process. This desilylation may also be operative for
the adducts 5-7.
The same type of product as 34 could be obtained from other
combinations of enynes and aldehydes including a heteroaro-
matic aldehyde, aliphatic aldehydes, and an enyne having a
functional group, the results of which are summarized in Table
3. In all cases, a virtually single isomer was isolated, and its
stereochemistry was assigned based on the assumption that the
addition took place in the same manner as the case of 34.
Synthetically, compounds of a similar structure to those in Table
3 could be prepared by the previously reported allenyne
cyclization with 1 followed by the addition of aldehydes.19
However, monosubstituted terminal allene 46 was not an
acceptable substrate in this allenyne cyclization, failing to furnish
the titanacycle 47 and, consequently, the corresponding adduct
34 (eq 6). Thus, the present cyclization starting from far more
easily available enynes followed by dehydrogenation and trap
Unusual Coupling Reaction with Aldehydes. η5-Cyclopen-
tadienyl ligands once complexed to titanium and zirconium are
difficult to exchange or remove. Considering this point, we
thought that one important feature of dialkoxytitanacycles could
be characterized by easy modification of their ligands. In an
extreme case, the alkoxy ligand could be removed from the
metal, which is, in other words, the reduction of the metal center.
A few methods are available for this latter process. For example,
the action of 2 equiv of a Grignard reagent to Ti(IV)(OR)4
generates (η2-alkene)Ti(II)(OR)2,15 as amply demonstrated in
the generation of 1.4 A related reaction, involving the removal
of a Cl ligand, is the treatment of a Cp2Ti(IV)Cl2 with 1 equiv
of an appropriate Grignard reagent, giving Cp2Ti(III)Cl.16
Under the hypothesis that a Grignard reagent would reduce
the dialkoxytitanacycle as described above, we carried out the
following experiment (eq 5). After the enyne 10 was treated
(17) The mechanistic rationale for this unusual reaction could be proposed
as follows. The formation of the benzaldehyde adduct 34 along with the
conjugated diene 35 (eq 5), the latter of which should arise from the simple
protonation of the same intermediate, could assume the intermediate
generation of the new titanacycle 40 in the following equation. It should
be noted that the generation of 40 is triggered by the injection of aldehyde,
because simple hydrolysis of the intermediate 36 after the treatment with
i-PrMgCl but before the addition of aldehyde merely yields the ordinary
cyclization product 33 shown in eq 5 in 88% yield but no trace of the
conjugated diene 35. Thus, in the possible reaction pathway from 11 to 40,
the added aldehyde plays a critical role. One-electron reduction of the
aldehyde with the low-valent titanacycle 36 via 37 would generate a radical
species such as 38,18 which abstracts the nearby hydrogen of the titanacycle
to give the radical intermediate 39. This radical intermediate collapses to
give the new titanacycle 40 with hydrogen radical abstraction or radical
disproportionation.
with 1 in the standard way, the solution of 11 was stirred with
a slight excess of i-PrMgCl at -50 °C for an additional 2 h. To
the resultant dark-brown mixture was added excess benzalde-
hyde at the same temperature. The reaction was warmed to an
ice-bath temperature, during which the color of the solution
turned light red. After aqueous workup, the normal adduct 13,
the same as the one in Scheme 1, was obtained in low yield
and with inferior diastereoselectivity. However, unexpectedly,
the main product in this reaction was a new adduct 34, which
was obtained virtually as a single stereoisomer and could be
(18) Generation of R-oxy radicals by reduction of aldehydes and ketones
with low-valent titanium reagents has been widely accepted as a step of
the pinacol-type coupling reactions. For review, see: (a) Lenoir, D. Synthesis
1989, 883. (b) Robertson, G. M. In ComprehensiVe Organic Synthesis; Trost,
B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 3, p 563. (c)
For latest reports, see: Barden, M. C.; Schwartz, J. J. Am. Chem. Soc. 1996,
118, 5484. (d) Gansa¨uer, A. Synlett 1997, 457. (e) For other radical reactions
induced by a low-valent titanium complex, see: RajanBabu, T. V.; Nugent,
W. A. J. Am. Chem. Soc. 1994, 116, 986 and references therein.
(19) Urabe, H.; Takeda, T.; Hideura, D.; Sato, F. J. Am. Chem. Soc.
1997, 119, 11295.
(13) (a) Luh, T.-Y.; Wong, K.-T. Synthesis 1993, 349. (b) Fringuelli,
F.; Taticchi, A. Dienes in the Diels-Alder Reaction; Wiley: New York,
1990.
(14) (a) Harada, K.; Urabe, H.; Sato, F. Tetrahedron Lett. 1995, 36, 3203.
(b) Sato, F.; Tanaka, Y.; Sato, M. J. Chem. Soc., Chem. Commun. 1983,
165.
(15) Kulinkovich, O. G.; Sviridov, S. V.; Vasilevski, D. A. Synthesis
1991, 234.
(16) (a) Martin, H. A.; Jellinek, F. J. Organomet. Chem. 1968, 12, 149.
(b) Martin, H. A.; Jellinek, F. J. Organomet. Chem. 1967, 8, 115.

Allylation of Bicyclic Titanacyclopentenes
J. Am. Chem. Soc., Vol. 121, No. 6, 1999 1249
Table 3. Cyclization of Enynes Followed by Dehydrogenation and
Table 4. Copper-Mediated Allylation of Titanacyclopentene 3
(eq 7)
Trap with Aldehydesa
copper salt
(equiv)
temp period
yield of
regio-
selectivity
entry
(°C)
(h)
48a (%)
1
2
none
none
-50
1
1
<trace
messy
products
0
3
4
5
6
Li2Cu(CN)Cl2 (0.05) -50
3
24
LiCu(Th)(CN)b (0.05)
LiCu(Th)(CN) (1)
Li2Cu(CN)Cl2 (1)
0
-50
-50
0.5 30
3
3
66
90 (82)
>95:<5
a Overall yield from enyne 2 determined by 1H NMR spectroscopy.
Isolated yield in parentheses. b Th ) thienyl.
Grignard reagents that could be transmetalated to the copper
reagents in a more straightforward manner.
We attempted the alkylation of the aforementioned titanacy-
clopentenes and cyclopentadienes with allyl bromide, but these
reactions failed to give the desired products, which was not
unexpected based on the aforementioned precedents. To sub-
stantiate this transformation, a copper-assisted reaction of
titanacyclopentene 3 was examined as shown in eq 7.
a For reaction conditions, see eq 5. b Products were isolated as a
virtually single stereoisomer. There is no evidence that other isomers
were formed in more than trace amounts.
Some variations of reagents and conditions are summarized
in Table 4. With a catalytic amount of a copper salt, the reaction
did proceed to some extent at -50 °C, but the reaction stopped
at low conversion (entry 3). This low conversion could not be
improved by raising the reaction temperature (entry 4). However,
with a stoichiometric amount of the copper, the reaction
proceeded very cleanly at low temperature to give the allylation
product in good yield (entry 6).23 Of the two copper reagents
investigated, Li2Cu(CN)Cl2 afforded a somewhat better yield
(entries 5 and 6). Similarly, a cyclohexane derivative could be
obtained as shown in entry 2, Table 5.
with aldehydes offers a complementary method to prepare
adducts that are not accessible by the allenyne cyclization.
Although the exact mechanism of the above reaction has not
been necessarily elucidated yet, it denotes a new behavior of
metallacycles of group 4 transition metals. The scission of the
C-H bond of the titanacycle to serve the generation of reactive
intermediates promoting the unexpected carbon-carbon bond
formation is an interesting entry to the activation of nonfunc-
tionalized C-H bonds with transition metal compounds, which
is a current interest in organic synthesis.20
Copper-Mediated Mono-allylation. Organotitanium reagents
have been less frequently utilized in substitution reactions of
alkyl halides and related compounds, as they generally show
diminished nucleophilicity toward these substrates as compared
to the corresponding lithium and Grignard reagents.8 Trans-
metalation of titanium compounds to another metallic species
such as copper reagents might increase their utility. However,
few attempts along this line have been made,21,22 because the
titanium reagents are generally prepared from lithium or
More importantly, a titanacyclopentadiene also undergoes the
copper-mediated mono-allylation. The transmetalation of ti-
tanacyclopentadiene to copper should be carried out again in
the presence of a stoichiometric amount of copper salt and at a
low temperature around -50 °C. While the regioselection
between the silyl and phenyl substituents shows no particular
preference (entry 3, Table 5), the titanacyclopentadiene having
the silyl and alkyl groups showed good selectivity as high as
9:1 (entry 4). The stereochemistries of the newly formed tri-
and tetra-substituted double bonds of 53 as well as 48 have
1
been confirmed by NOE study of H NMR spectroscopy (see
the Experimental Section). The reaction stopped at the mono-
allylation stage, and another remaining carbon-titanium bond
could be identified by deuteration (entry 4). In contrast to a
copper-mediated bis-allylation of Cp2-zirconacyclopentadienes
reported recently,24 the above process embodies the first mono-
allylation of metallacyclopentadienes of group 4 transition
metals, in a regioselective manner in a certain case. It is
interesting to note that the carbon-carbon bond extension after
the bicyclization of a diyne could be achieved in both directions
(20) Shilov, A. E.; Shul’pin, G. B. Chem. ReV. 1997, 97, 2879 and
references therein.
(21) Titanium/copper transmetalation is quite rare (see ref 8a, p 89) and
has been only documented in the reactions of alkyltitanium reagents. Arai,
M.; Lipshutz, B. H.; Nakamura, E. Tetrahedron 1992, 48, 5709.
(22) Copper-promoted reactions of group 4 transition metal intermediates
have been centered on zirconium compounds. For reviews, see: (a) Wipf,
P. Synthesis 1993, 537. (b) Wipf, P. Jahn, H. Tetrahedron 1996, 52, 12853.
(c) Lipshutz, B. H. Acc. Chem. Res. 1997, 30, 277. (d) Wipf, P.; Xu, W.;
Takahashi, H.; Jahn, H.; Coish, P. D. G. Pure Appl. Chem. 1997, 69, 639.
(e) Kotora, M.; Xi, Z.; Takahashi, T. J. Synth. Org. Chem. Jpn. 1997, 55,
958.
(23) Copper-mediated allylation of Cp2-zirconacyclopentenes has been
reported. Kasai, K.; Kotora, M.; Suzuki, N.; Takahashi, T. J. Chem. Soc.,
Chem. Commun. 1995, 109.
(24) Bis-allylation of Cp2-zirconacyclopentadienes in the presence of a
copper salt has been reported. (a) Takahashi, T.; Kotora, M.; Kasai, K.;
Suzuki, N. Organometallics 1994, 13, 4183. (b) Kotora, M.; Umeda, C.;
Ishida, T.; Takahashi, T. Tetrahedron Lett. 1997, 38, 8355.

1250 J. Am. Chem. Soc., Vol. 121, No. 6, 1999
Urabe and Sato
Table 5. Cyclization of Enynes or Diynes Followed by
Copper-Mediated Alkylation with Allyl Bromide
10 was prepared by Wittig methylenation of 5-dodecynal (Ph3PMe+Br-,
BuLi, Et2O). Diyne 31 was prepared by (i) successive alkylation of
benzylamine with 3-butynyl tosylate ((i-Pr)2NEt, cat. NaI, DMF) and
phenylpropargyl bromide (K2CO3, CH3CN) and (ii) silylation (BuLi,
Me3SiCl, THF). Other enynes and diynes 16, 26, 29, and 49 were
prepared by alkylation of appropriate acetylenic iodides with lithiated
(trimethylsilyl)acetylene in a standard manner. Similarly, 44 was
prepared by alkylation of lithiated 4-[(tert-butyl)dimethylsiloxy]-1-
butyne with 5-bromo-1-pentene.
4,4-Bis(benzyloxymethyl)-1-(trimethylsilyl)-6-hepten-1-yne (2). 1H
NMR δ 0.13 (s, 9 H), 2.23 (d, J ) 7.7 Hz, 2 H), 2.30 (s, 2 H), 3.30-
3.42 (m, 4 H), 4.49 (s, 4 H), 5.04 (br d, J ) 10 Hz, 1 H), 5.08 (br d,
J ) 17 Hz, 1 H), 5.65-5.84 (symmetrical m, 1 H), 7.22-7.39 (m, 10
H); 13C NMR δ 0.15, 23.56, 36.36, 42.22, 71.89, 73.31, 86.64, 104.33,
117.96, 127.32, 128.32, 129.22, 133.93, 138.80; IR (neat) 3075, 3040,
2970, 2900, 2870, 2175, 1640, 1500, 1480, 1450, 1360, 1245, 1200,
1100, 1020, 1000, 990, 910, 840, 750, 725, 690 cm-1. Anal. Calcd for
C26H34O2Si: C, 76.80; H, 8.43. Found: C, 76.54; H, 8.46.
Confirmation of the Presence of Titanacycle 3. 1,1-Bis(benzyl-
oxymethyl)-3-[(E)-(trimethylsilyl)methylene]-4-methylcyclopentane
1
(55). H NMR δ 0.09 (s, 9 H), 1.03 (d, J ) 6.7 Hz, 3 H), 1.07 (dd, J
) 10.8, 12.8 Hz, 1 H), 1.94 (dd, J ) 8.3, 12.9 Hz, 1 H), 2.32 (br s, 2
H), 2.40-2.57 (m, 1 H), 3.30-3.42 (m, 4 H), 4.50 (s, 4 H), 5.23 (br
s, 1 H), 7.20-7.37 (m, 10 H); 13C NMR δ -0.19, 18.74, 39.24 (two
carbons), 39.88, 45.80 (quaternary carbon), 73.07, 73.18 (two carbons),
74.88, 117.19, 127.29, 127.32 (two types of carbons), 127.39, 128.23
(two types of carbons), 138.91 (two types of carbons), 165.85; IR (neat)
a This refers to the step of the copper-mediated allylation according
to entry 6, Table 4. b Workup with 1 N DCl.
3025, 2850, 1620, 1450, 1355, 1240, 1200, 1090, 835, 730, 690 cm-1
.
Scheme 3. Profile of the Reactions of a
Dialkoxycyclopentadiene
Anal. Calcd for C26H36O2Si: C, 76.42; H, 8.88. Found: C, 76.55; H,
8.92.
Typical Procedure for the Addition of Titanacyclopentenes to
Aldehydes in the Presence of Ti(O-i-Pr)2Cl2. (RS)-2-[(2RS)-(E)-2-
Methyl-4,4-bis(benzyloxymethyl)cyclopentylidene]-2-(trimethylsilyl)-
1-cyclohexylethanol (5). To a stirred mixture of 4,4-bis(benzyloxym-
ethyl)-1-(trimethylsilyl)-6-hepten-1-yne (2) (50 mg, 0.123 mmol) and
Ti(O-i-Pr)4 (0.045 mL, 0.154 mmol) in 1.5 mL of Et2O was added
i-PrMgCl (1.50 M in ether, 0.226 mL, 0.338 mmol) dropwise at -78
°C under argon. After stirring for 30 min, the solution was warmed to
-50 °C over 30 min and kept at this temperature for 2 h. After the
solution had been recooled to -78 °C, Ti(O-i-Pr)2Cl2 (1.2 M in ether,
0.128 mL, 0.154 mmol) was added, and the mixture was stirred at -78
°C for another 30 min. Cyclohexanecarbaldehyde (0.029 mL, 0.239
mmol) was then added, and the reaction mixture was stirred at the same
temperature for 10 min. After the solution was rapidly allowed to warm
to 0 °C and was kept at the same temperature for 30 min, the reaction
was terminated by the addition of aqueous 1 N HCl. The organic layer
was separated, washed with aqueous NaHCO3 solution, dried (Na2-
SO4), and concentrated to an oil, which was chromatographed on silica
gel (hexanes-ether) to afford the title compound (32 mg, 50%) as a
simply by switching the electrophiles as shown in Scheme 3,
making a flexible synthetic design possible.
Conclusion
The bicyclization of enynes and diynes mediated by low-
valent titanium complex 1 and the subsequent, selective addition
to aldehydes show new applications that are complementary to
those of similar metallacycles of other group 4 transition metals.
The copper-mediated allylation of titanacycles, which is a new
entry to the titanium/copper bimetallic system, provides another
method for the construction of a side chain. Since the necessary
reagents to generate the new cyclic organotitanium intermediates
are very inexpensive Ti(O-i-Pr)4 and a Grignard reagent, the
transformations described herein should offer an economical
way to achieve selective transformations by taking advantage
of the characteristic feature of organotitanium compounds.
Further study to disclose unique reactions based on dialkoxyti-
tanacyles is now in progress.
1
colorless oil. H and 13C NMR analyses confirmed that the product is
a single isomer. There was no evidence that more than a trace amount
of another diastereoisomer was present in a crude and purified product
by careful 1H NMR analysis. For the determination of the relative
stereochemistry, see text. 1H NMR δ 0.18 (s, 9 H), 0.85 (m, 2 H), 1.04
(d, J ) 7 Hz, 3 H), 1.08-1.30 (m, 4 H), 1.30 (dd, J ) 6, 15 Hz, 1 H),
1.43 (br d, J ) 12 Hz, 1 H), 1.50-1.80 (m, 4 H), 1.80 (dd, J ) 7.5,
15 Hz, 1 H), 2.13 (br d, J ) 13 Hz, 1 H), 2.23 (d, J ) 15 Hz, 1 H),
2.53 (d, J ) 15 Hz, 1 H), 2.89 (br sextet, J ) 7.2 Hz, 1 H), 3.19 (d,
J ) 8.5 Hz, 1 H), 3.24 (d, J ) 8.5 Hz, 1 H), 3.41 (d, J ) 8.5 Hz, 1 H),
3.51 (d, J ) 8.5 Hz, 1 H), 4.17 (d, J ) 7.7 Hz, 1 H), 4.38 (d, J ) 12
Hz, 1 H), 4.50 (d, J ) 12 Hz, 1 H), 4.53 (s, 2 H), 7.22-7.38 (m, 10
H); 13C NMR δ 2.06, 24.61, 26.40, 26.63 (two carbons), 30.56, 31.23,
35.30, 38.78, 39.23, 42.86, 46.04 (quaternary carbon), 72.85, 73.14,
73.24, 75.15, 79.38, 127.31, 127.35, 127.39, 127.61, 128.20, 128.23,
133.97, 138.70, 138.94, 159.96; IR (neat) 3500 (OH), 3100, 3080, 3050,
2950, 2860, 1460, 1250, 1100, 840 cm-1. Anal. Calcd for C33H48O3Si:
C, 76.10; H, 9.29. Found: C, 75.92; H, 9.38.
Experimental Section
General. 1H and 13C NMR spectra were taken on a Varian Gemini-
300 spectrometer at 300 and 75 MHz, respectively. CDCl3 was used
as the solvent. Chemical shifts are reported in parts per million shift
(δ value) from Me4Si (δ 0 ppm for 1H) or based on the middle peak of
the solvent (CDCl3) (δ 77.00 ppm for 13C NMR) as an internal standard,
unless otherwise noted. Signal patterns are indicated as br, broad; s,
singlet; d, doublet; t, triplet; q, quartet; or m, multiplet. Coupling
constants (J) are given in hertz. Infrared (IR) spectra were recorded on
a JASCO A-100 spectrometer and are reported in wavenumbers (cm-1).
All reactions were carried out under argon. Enyne 2 and diyne 23 were
prepared by the following sequence: (i) mono- or dialkylation of diethyl
allylmalonate or diethyl malonate with propargyl bromide (NaH, THF),
(ii) reduction of the ester (LiAlH4), (iii) benzylation of the diol (benzyl
bromide, NaH, THF), and (iv) silylation (BuLi, Me3SiCl, THF). Enyne
Typical Procedure for the Addition of Titanacyclopentenes to
Aldehydes in the Presence of Ti(O-i-Pr)3Cl. (RS)-2-[(2RS)-(E)-2-
Methyl-4,4-bis(benzyloxymethyl)cyclopentylidene]-2-(trimethylsilyl)-
1-phenylethanol (6). To a mixture of 4,4-bis(benzyloxymethyl)-1-
(trimethylsilyl)-6-hepten-1-yne (2) (50 mg, 0.123 mmol) and Ti(O-i-

Allylation of Bicyclic Titanacyclopentenes
J. Am. Chem. Soc., Vol. 121, No. 6, 1999 1251
J ) 6, 14 Hz, 1 H), 1.68 (br s, 1 H, OH), 1.95 (dd, J ) 8, 14 Hz, 1 H),
2.35 (d, J ) 15 Hz, 1 H), 2.59 (d, J ) 15 Hz, 1 H), 3.00 (br sextet,
J ) 7 Hz, 1 H), 3.29 (d, J ) 8.5 Hz, 1 H), 3.37 (d, J ) 8.5 Hz, 1 H),
3.46 (d, J ) 8.5 Hz, 1 H), 3.57 (d, J ) 8.5 Hz, 1 H), 4.47 (d, J ) 13
Hz, 1 H), 4.55 (s, 2 H), 4.58 (d, J ) 13 Hz, 1 H), 5.78 (br s, 1 H),
7.20-7.40 (m, 15 H).
Figure 4. 1H NMR spectra of authentic 13 and samples 6 and 7.
Upfield shifts are shown in boldface.
(RS)-1-[(2RS)-(E)-2-Methyl-4,4-bis(benzyloxymethyl)cyclopen-
tylidene]-1-(trimethylsilyl)-4-phenyl-2-butanol (7). 1H NMR δ 0.18
(s, 9 H), 0.87 (d, J ) 7 Hz, 3 H), 1.22 (dd, J ) 6, 14 Hz, 1 H), 1.30
(br s, 1 H, OH), 1.55 (m, 1 H), 1.85 (dd, J ) 8.5, 14 Hz, 1 H), 2.05
(m, 1 H), 2.18 (d, J ) 15 Hz, 1 H), 2.47 (d, J ) 15 Hz, 1 H), 2.64 (m,
1 H), 2.78 (br sextet, J ) 7.5 Hz, 1 H), 2.86 (m, 1 H), 3.19 (d, J ) 8.5
Hz, 1 H), 3.24 (d, J ) 8.5 Hz, 1 H), 3.40 (d, J ) 8.5 Hz, 1 H), 3.50
(d, J ) 8.5 Hz, 1 H), 4.37 (d, J ) 12 Hz, 1 H), 4.49 (d, J ) 12 Hz, 1
H), 4.52 (s, 2 H), 4.54 (d, J ) 10 Hz, 1 H), 7.15-7.35 (m, 15 H).
Decoupling study showed that the proton at δ 2.05 ppm (PhCH2CH2)
is vicinal (or geminal) to the protons at δ 1.55 (PhCH2CH2), 2.64
(PhCH2), 2.86 (PhCH2), and 4.54 (CHOH) ppm. 13C NMR δ 2.06,
23.46, 33.10, 35.54, 38.84, 39.27, 39.49, 46.50 (quaternary carbon),
72.47, 73.17, 73.25, 74.10, 75.04, 125.76, 127.35, 127.55, 128.20,
128.25, 128.35, 128.55, 135.75, 138.80, 138.94, 142.21, 158.40. Peaks
in the region between δ 125.76 and 128.55 ppm may include more
than two types of carbons. IR (neat) 3600 (OH), 3100, 3080, 3040,
2950, 2860, 1950, 1880, 1810, 1720, 1610, 1500, 1460, 1370, 1250,
1210, 1100, 1030, 920, 840, 750, 700 cm-1. Anal. Calcd for C35H46O3-
Si: C, 77.44; H, 8.54. Found: C, 77.67; H, 8.54.
Pr)4 (0.045 mL, 0.154 mmol) in 1 mL of Et2O was added i-PrMgCl
(1.50 M in ether, 0.226 mL, 0.338 mmol) dropwise at -78 °C under
argon. After stirring for 30 min, the solution was warmed to -50 °C
over 30 min and kept at this temperature for 2 h. After the addition of
Ti(O-i-Pr)3Cl (2 M in ether, 0.077 mL, 0.154 mmol), the mixture was
stirred at -50 °C for another 30 min. Benzaldehyde (0.019 mL, 0.185
mmol) was then added, and the reaction mixture was stirred at the same
temperature for 1.5 h. After the solution was allowed to warm to -40
°C over 30 min, the reaction was terminated at that temperature by the
addition of aqueous 1 N HCl. The organic layer was separated, washed
with aqueous NaHCO3 solution, dried (Na2SO4), and concentrated to
an oil, which was chromatographed on silica gel (hexanes-ether) to
afford the title compound (34 mg, 54%) as a colorless oil. The
stereochemistry of the olefinic moiety of the product was confirmed
by an NOE study. 1H NMR δ -0.05 (s, 9 H), 0.97 (d, J ) 7 Hz, 3 H),
1.30 (dd, J ) 6, 14 Hz, 1 H), 1.70 (br s, 1 H, OH), 1.95 (dd, J ) 8, 14
Hz, 1 H), 2.39 (d, J ) 15 Hz, 1 H), 2.61 (d, J ) 15 Hz, 1 H), 2.95 (br
sextet, J ) 7.5 Hz, 1 H), 3.28 (d, J ) 8.5 Hz, 1 H), 3.32 (d, J ) 8.5
Hz, 1 H), 3.46 (d, J ) 8.5 Hz, 1 H), 3.55 (d, J ) 8.5 Hz, 1 H), 4.42
(d, J ) 12 Hz, 1 H), 4.52 (d, J ) 12 Hz, 1 H), 4.54 (d, J ) 12 Hz, 1
H), 4.57 (d, J ) 12 Hz, 1 H), 5.70 (br s, 1 H), 7.20-7.40 (m, 15 H).
The following NOE study confirmed the assigned stereochemistry.
Irradiation of the proton at δ 0.97 ppm (Me) showed 5% enhancement
each at the peaks of δ 1.30 (cyclopentane CH cis to Me), 2.95 (CHMe),
and 5.70 ppm (CHOH). Irradiation of the proton at δ 2.95 ppm (CHMe)
showed 1%, 5%, and 27% enhancement at the peaks of δ 0.97 (Me),
1.95 (cyclopentane CH trans to Me), and 5.70 ppm (CHOH),
respectively. Alternatively, irradiation of the proton at δ 5.70 ppm
(CHOH) showed 1% and 22% enhancement at the peaks of δ 0.97
(Me) and 2.95 ppm (CHMe). 13C NMR δ 1.21, 23.82, 35.52, 39.34,
39.51, 46.82 (quaternary carbon), 72.48, 73.25, 73.29, 74.25, 74.96,
126.09, 126.52, 127.35, 127.40, 127.44, 127.61, 127.85, 128.23, 128.27,
133.83, 138.75, 138.92, 143.83, 160.63. Peaks in the region between
δ 126.09-128.27 ppm may include more than two types of carbons.
IR (neat) 3580 (OH), 3100, 3075, 3050, 2960, 2930, 2900, 2860, 1620,
1500, 1460, 1370, 1250, 1100, 1030, 840, 750, 740, 700 cm-1. Even
after considerable effort, we could not obtain the correct elemental
analysis for this particular compound due apparently to its fragile nature.
The ratio (>95:<5) of the diastereoisomers, which could not be
separated by the chromatography, was determined by 1H NMR
spectroscopy in comparison with an authentic sample of the minor
diastereoisomer (vide infra). For the determination of the relative
stereochemistry, see text and Figure 4 shown above.
The ratio (96:4) of the diastereoisomers, which could not be separated
1
by the chromatography, was determined by H NMR spectroscopy in
comparison with an authentic sample of the minor diastereoisomer (vide
infra). For the determination of the relative stereochemistry, see text
and Figure 4 shown above.
Preparation of the Minor Diastereoisomer of 7 (eq 9). Treatment
of 7 with 3 equiv of PCC in CH2Cl2 at room temperature for 1 h
afforded 1-[(E)-2-methyl-4,4-bis(benzyloxymethyl)cyclopentylidene]-
1
1-(trimethylsilyl)-4-phenyl-2-butanone in 51% yield. H NMR δ 0.11
(s, 9 H), 0.96 (d, J ) 7 Hz, 3 H), 1.25 (dd, J ) 7, 14 Hz, 1 H), 1.81
(dd, J ) 8, 14 Hz, 1 H), 2.26 (d, J ) 15 Hz, 1 H), 2.41 (d, J ) 15 Hz,
1 H), 2.53 (br sextet, J ) 7 Hz, 1 H), 2.68 (m, 2 H), 2.87 (q, J ) 8 Hz,
2 H), 3.19 (d, J ) 8.5 Hz, 1 H), 3.26 (d, J ) 8.5 Hz, 1 H), 3.40 (d, J
) 8.5 Hz, 1 H), 3.48 (d, J ) 8.5 Hz, 1 H), 4.45 (d, J ) 8 Hz, 1 H),
4.48 (d, J ) 8 Hz, 1 H), 4.50 (s, 2 H), 7.15-7.35 (m, 15 H); IR (neat)
3080, 3040, 2960, 2940, 2860, 1680, 1610, 1460, 1250, 1100, 840,
750, 700 cm-1. This ketone was given back to a 4:6 mixture of 7 and
its diastereoisomer in a quantitative yield via reduction with LiAlH4
(1 equiv) in ether at room temperature for 20 min. 1H NMR δ
(characteristic peaks are shown) 0.21 (s, 9 H), 1.08 (d, J ) 7 Hz, 3 H),
4.64 (t, J ) 8 Hz, 1 H).
Preparation of the Minor Diastereoisomer of 6 (eq 8). Treatment
of 6 with 3 equiv of PCC in CH2Cl2 at room temperature for 1 h
afforded R-[(E)-2-methyl-4,4-bis(benzyloxymethyl)cyclopentylidene]-
R-(trimethylsilyl)acetophenone in 41% yield. 1H NMR δ 0.12 (s, 9 H),
0.88 (d, J ) 8 Hz, 3 H), 1.26 (dd, J ) 7, 14 Hz, 1 H), 1.80 (dd, J )
8, 14 Hz, 1 H), 2.41 (d, J ) 15 Hz, 1 H), 2.52 (br sextet, J ) 7 Hz, 1
H), 2.64 (d, J ) 15 Hz, 1 H), 3.30 (d, J ) 8.5 Hz, 1 H), 3.36 (d, J )
8.5 Hz, 1 H), 3.44 (d, J ) 8.5 Hz, 1 H), 3.52 (d, J ) 8.5 Hz, 1 H),
4.52 (s, 4 H), 7.20-7.35 (m, 10 H), 7.40 (t, J ) 8 Hz, 2 H), 7.52 (t,
J ) 8 Hz, 1 H), 7.86 (d, J ) 8 Hz, 2 H). This ketone was given back
to a 2:8 mixture of 6 and its diastereoisomer in a quantitative yield via
reduction with LiAlH4 (1 equiv) in ether at room temperature for 20
(RS)-2-[(2RS)-(E)-2-(Deuteriomethyl)-4,4-bis(benzyloxymethyl)-
cyclopentylidene]-2-(trimethylsilyl)-1-cyclohexylethanol (8). This
showed the same 1H NMR spectrum as that of the nondeuterated
1
min. H NMR δ -0.09 (s, 9 H), 1.21 (d, J ) 7 Hz, 3 H), 1.32 (dd,

1252 J. Am. Chem. Soc., Vol. 121, No. 6, 1999
Urabe and Sato
compound except that the peaks at δ 1.03 ppm (br d, J ) 6.7 Hz, 2 H)
and 2.88 ppm (br quintet, J ) 7 Hz, 1 H) were observed in place of
those at 1.04 ppm (d, J ) 7 Hz, 3 H) and 2.89 ppm (br sextet, J ) 7.2
Hz, 1 H). Deuterium incorporation was determined to be >98%.
Typical Procedure for the Iodinolysis of the Oxatitanacycle such
as 4. (RS)-2-[(2RS)-(E)-2-(Iodomethyl)-4,4-bis(benzyloxymethyl)-
cyclopentylidene]-2-(trimethylsilyl)-1-cyclohexylethanol (9). The
same reaction was carried out with 4,4-bis(benzyloxymethyl)-1-
(trimethylsilyl)-6-hepten-1-yne (2) (40 mg, 0.0984 mmol), Ti(O-i-Pr)4
(0.036 mL, 0.123 mmol), i-PrMgCl (1.44 M in ether, 0.188 mL, 0.271
mmol), Ti(O-i-Pr)2Cl2 (1.25 M in ether, 0.098 mL, 0.123 mmol), and
cyclohexanecarbaldehyde (0.024 mL, 0.197 mmol). In place of the
aqueous workup, the solution was cooled to -78 °C, and I2 (55 mg,
0.216 mmol) in 0.4 mL of THF was rapidly added. The solution was
warmed to 0 °C and stirred at this temperature for 10 min. The reaction
was terminated by the addition of 1 N HCl. The organic layer was
separated and washed successively with aqueous NaHCO3 solution and
Na2S2O3 solution, dried (Na2SO4), and concentrated to an oil, 1H NMR
analysis of which showed the formation of the title compound in 58%
yield. Purification on preparative TLC afforded a pure sample (23 mg,
37%) as an oil, which was rather unstable and suddenly decomposed
CH2O) showed a 27% enhancement to the proton at δ 3.23 ppm (endo-
CH2O), but no enhancement to the proton at δ 4.91 ppm (CHPh). 13
C
NMR δ 13.92, 22.39, 23.68, 27.55, 28.18, 29.09, 29.50, 29.59, 31.45,
40.33, 70.19, 79.43, 127.86, 128.37, 128.40, 129.35, 137.94, 141.77;
IR (neat) 3070, 3025, 2960, 2930, 2860, 1455, 1105, 1065, 700 cm-1
.
1-Phenyl-8-(trimethylsilyl)-1,7-octadiyne (16). 1H NMR δ 0.15 (s,
9 H), 1.70 (m, 4 H), 2.29 (distorted t, J ) 7 Hz, 2 H), 2.45 (distorted
t, J ) 7 Hz, 2 H), 7.27 (m, 3 H), 7.39 (m, 2 H); 13C NMR δ 0.17,
18.97, 19.46, 27.78, 27.82, 80.91, 84.76, 89.80, 107.05, 124.01, 127.52,
128.17, 131.55; IR (neat) 3080, 3040, 2960, 2860, 2180, 1500, 1250,
840, 760, 690 cm-1. Anal. Calcd for C17H22Si: C, 80.25; H, 8.71.
Found: C, 80.15; H, 8.70.
Verification of the Presence of Titanacycle 17 by Hydrolysis.
1-[(E)-Benzylidene]-2-[(E)-(trimethylsilyl)methylene]cyclohexane (18).
1H NMR δ 0.16 (s, 9 H), 1.61 (br quintet, J ) 6 Hz, 2 H), 1.70 (br
quintet, J ) 6 Hz, 2 H), 2.44 (t, J ) 6 Hz, 2 H), 2.55 (t, J ) 6 Hz, 2
H), 5.57 (s, 1 H), 6.56 (s, 1 H), 7.18-7.35 (m, 5 H); 13C NMR δ 0.17,
26.16, 26.76, 29.96, 34.46, 123.28, 123.38, 126.20, 127.96, 129.31,
138.05, 146.07, 159.86; IR (neat) 3090, 3070, 3040, 2960, 2940, 2860,
1600, 1500, 1450, 1250, 930, 920, 850, 770, 700 cm-1
.
Typical Procedure for the Addition of Titanacyclopentadienes
to Aldehydes. 1-[(E)-2-[(E)-Benzylidene]cyclohexylidene]-1-(tri-
methylsilyl)-4-phenyl-2-butanol (20). To a stirred mixture of 1-phenyl-
8-(trimethylsilyl)-1,7-octadiyne (16) (30 mg, 0.118 mmol) and Ti(O-
i-Pr)4 (0.043 mL, 0.148 mmol) in 1.5 mL of Et2O was added i-PrMgCl
(1.44 M in ether, 0.225 mL, 0.325 mmol) dropwise at -78 °C under
argon. After stirring for 30 min, the solution was warmed to -50 °C
over 30 min and kept at this temperature for 4 h. After the solution
had been recooled to -78 °C, Ti(O-i-Pr)2Cl2 (1.33 M in ether, 0.111
mL, 0.148 mmol) was added, and the mixture was stirred at -78 °C
for another 30 min. 3-Phenylpropanal (0.016 mL, 0.118 mmol) was
added, and the solution was rapidly allowed to warm to 0 °C with
stirring. After the mixture was allowed to stand in a refrigerator (2-3
°C) overnight, the reaction was terminated by the addition of aqueous
1 N HCl at 0 °C. The organic layer was separated and washed with
aqueous NaHCO3 solution, dried (Na2SO4), and concentrated to an oil,
which was chromatographed on silica gel (hexanes-ether) to afford
1
completely. H NMR δ 0.16 (s, 9 H), 0.85 (m, 2 H), 0.89 (dd, J ) 7,
15 Hz, 1 H), 1.1-1.32 (m, 4 H), 1.44 (br d, J ) 12 Hz, 1 H), 1.50-
1.80 (m, 4 H), 1.81 (dd, J ) 7.5, 15 Hz, 1 H), 2.08 (br d, J ) 14 Hz,
1 H), 2.34 (d, J ) 15 Hz, 1 H), 2.55 (d, J ) 15 Hz, 1 H), 3.10 (d, J
) 8 Hz, 1 H), 3.16 (m, 1 H), 3.18 (d, J ) 8.5 Hz, 1 H), 3.23 (d, J )
8.5 Hz, 1 H), 3.34 (dd, J ) 2, 8 Hz, 1 H), 3.44 (d, J ) 8.5 Hz, 1 H),
3.48 (d, J ) 8.5 Hz, 1 H), 4.07 (d, J ) 7.7 Hz, 1 H), 4.37 (d, J ) 12
Hz, 1 H), 4.49 (d, J ) 12 Hz, 1 H), 4.54 (s, 2 H), 7.23-7.39 (m, 10
H); IR (neat) 3400 (OH), 3040, 1460, 1250, 1100, 740, 700 cm-1
.
1-Tridecen-6-yne (10). 1H NMR δ 0.88 (t, J ) 7 Hz, 3 H), 1.18-
1.62 (m, 13 H), 2.13 (m, 6 H), 4.96 (d, J ) 10 Hz, 1 H), 5.02 (d, J )
17 Hz, 1 H), 5.80 (ddt, J ) 10, 17, 7 Hz, 1 H); 13C NMR δ 14.35,
18.49, 19.06, 22.90, 28.67, 28.87, 29.45, 31.71, 33.15, 80.16, 81.02,
115.38, 138.66; IR (neat) 3080, 2930, 2860, 1640, 1460, 1440, 1335,
990, 915 cm-1. Anal. Calcd for C13H22: C, 87.56; H, 12.44. Found:
C, 87.72; H, 12.16.
1
(RS)-2-[(2SR)-(Z)-2-Methyl-1-cyclopentylidene]-1-phenyl-1-oc-
the title compound (33 mg, 72%) as a colorless oil. H NMR δ 0.30
1
tanol (13). H NMR δ 0.89 (t, J ) 7 Hz, 3 H), 1.08 (d, J ) 7 Hz, 3
(s, 9 H), 1.51 (br s, 1 H, OH), 1.68 (m, 4 H), 1.84 (m, 1 H), 2.06 (m,
1 H), 2.47 (br m, 4 H), 2.60 (ddd, J ) 6.6, 9.8, 13.5 Hz, 1 H), 2.75 (m,
1 H), 4.85 (dd, J ) 5.1, 8.6 Hz, 1 H), 6.17 (s, 1 H), 7.20-7.40 (m, 10
H). The following NOE study confirmed the stereochemical assign-
ments. Irradiation of the proton at δ 4.85 ppm (CHOH) showed a 7%
enhancement to that at δ 6.17 ppm (vinylic H). Alternatively, irradiation
of the proton at δ 6.17 ppm (vinylic H) showed a 7% enhancement to
that at δ 4.85 ppm (CHOH). 13C NMR δ 2.52, 28.00, 28.63, 31.65,
33.06, 37.48, 39.55, 74.64, 124.75, 125.67, 126.36, 128.11, 128.33 (may
involve two types of carbons), 128.93, 135.91, 137.38, 142.12, 144.33,
155.70; IR (neat) 3460 (OH), 3080, 3040, 2950, 2860, 1605, 1580,
1500, 1460, 1450, 1250, 1040, 860, 840, 740, 700 cm-1. Anal. Calcd
for C26H34OSi: C, 79.94; H, 8.77. Found: C, 80.14; H, 8.84. Further
structural confirmation was made by the selective removal of the vinylic
silyl group (vide infra).
H), 1.04-1.35 (m, 8 H), 1.58 (br s, 1 H, OH), 1.72 (m, 5 H), 1.95 (dt,
J ) 4, 12 Hz, 1 H), 2.26 (dd, J ) 8, 17 Hz, 1 H), 2.39 (ddd, J ) 4, 9,
17 Hz, 1 H), 3.00 (quintet, J ) 7 Hz, 1H), 5.74 (s, 1 H), 7.20-7.43
(m, 5 H); 13C NMR δ 13.90, 21.93, 22.42, 22.99, 29.28 (two carbons),
29.53, 29.87, 31.37, 34.70, 35.65, 73.91, 126.14, 126.77, 128.06, 131.86,
142.94, 147.98; IR (neat) 3360 (OH), 3090, 3065, 3030, 2960, 2925,
2860, 1495, 1450, 1375, 1020, 1000, 740, 700 cm-1 for an 85:15
mixture of the diastereoisomers. Anal. Calcd for C20H30O: C, 83.86;
H, 10.56. Found: C, 83.98; H, 10.47 for an 85:15 mixture of the
diastereoisomers.
(Minor) Diastereoisomer of 13. Characteristic peaks of the 1H NMR
spectrum are shown: δ 1.14 (d, J ) 7 Hz, 3 H), 3.04 (m, 1 H), 5.77
(s, 1 H).
(RS)-2-[(2SR)-(Z)-2-(Iodomethyl)-1-cyclopentylidene]-1-phenyl-
1
1-octanol (14). H NMR δ 0.90 (t, J ) 7 Hz, 3 H), 1.04-1.36 (m, 8
Desilylation of the Vinylic Trimethylsilyl Group of 20 (eq 3).
2-[(E)-Benzylidene]-1-[(Z)-2-(trimethylsilyloxy)-4-phenylbutylidene]-
cyclohexane. Treatment of 20 with a catalytic amount of KH in THF
at room temperature for 10 min14 afforded the title compound (82%)
H), 1.58 (br s, 1 H, OH), 1.77 (m, 4 H), 1.96 (m, 2 H), 2.32 (dd, J )
8, 16 Hz, 1 H), 2.43 (m, 1 H), 3.05 (dd, J ) 10.5, 12.6 Hz, 1 H),
3.21-3.31 (m, 2 H), 5.60 (s, 1 H), 7.23-7.40 (m, 5 H).
1
(3RS,6SR)-2-Hexyl-3-phenyl-4-oxa-1-bicyclo[4.3.0]nonene (15). 1H
NMR δ 0.83 (t, J ) 7 Hz, 3 H), 1.10-1.35 (m, 9 H), 1.62 (m, 2 H),
1.86 (m, 3 H), 2.35 (distorted t, J ) 7 Hz, 2 H), 2.62 (m, 1 H), 3.23
(t, J ) 10.5 Hz, 1 H), 4.24 (dd, J ) 4.5, 10.5 Hz, 1 H), 4.91 (q, J )
2 Hz, 1 H), 7.22-7.35 (m, 5 H). Decoupling of the proton at δ 2.62
ppm (bridgehead H) changed the following peaks: δ 3.23 ppm (t, J )
10.5 Hz, 1 H, endo-CH2O) f (distorted m); δ 4.24 ppm (dd, J ) 4.5,
10.5 Hz, 1 H, exo-CH2O) f (d, J ) 10.5 Hz); δ 4.91 ppm (q, J ) 2
Hz, 1 H, CHPh) f (br s). The following NOE study confirmed the
assigned stereochemistry. Irradiation of the peak at δ 2.62 ppm
(bridgehead H) showed a 3% enhancement to the proton at δ 4.24 ppm
(exo-CH2O). Irradiation of the peak at δ 3.23 ppm (endo-CH2O) showed
32% and 6% enhancement to the protons at δ 4.24 ppm (exo-CH2O)
and δ 4.91 ppm (CHPh). Irradiation of the peak at δ 4.24 ppm (exo-
after purification on silica gel (hexanes-ether). H NMR δ 0.08 (s, 9
H), 1.45-2.00 (m, 5 H), 2.10-2.40 (m, 3 H), 2.52-2.80 (m, 4 H),
4.59 (dt, J ) 5, 9 Hz, 1 H), 5.29 (d, J ) 9 Hz, 1 H), 6.11 (s, 1 H),
7.00-7.40 (m, 10 H). Protons at δ 4.59 ppm (CHOSiMe3) and at δ
5.29 ppm (CdCHCH(OSiMe3)) proved to be vicinal by a decoupling
experiment. The following NOE study further confirmed the stereo-
chemical assignments. Irradiation of the proton at δ 4.59 ppm
(CHOSiMe3) showed a 9% enhancement to that at δ 6.11 ppm (Cd
CHPh). Alternatively, irradiation of the proton at δ 6.11 ppm (Cd
CHPh) showed 10% enhancement each to that at δ 4.59 ppm
(CHOSiMe3) and that at δ 7.12 ppm (o-PhH) but no enhancement to
that at δ 5.29 ppm (CdCHCH(OSiMe3)).
1-[(E)-2-[(E)-Deuterio(phenyl)methylene]cyclohexylidene]-1-(tri-
methylsilyl)-4-phenyl-2-butanol (21). The 1H NMR spectrum was

Allylation of Bicyclic Titanacyclopentenes
J. Am. Chem. Soc., Vol. 121, No. 6, 1999 1253
virtually the same as that of the nondeuterated compound except that
the peak at δ 6.11 ppm (vinylic H) disappeared (99% deuterium
incorporation). The 13C NMR spectrum was virtually the same as that
of the nondeuterated compound except that the peak at δ 124.75 ppm
(CdCPh) was not observed under the experimental conditions.
1240, 1100, 840, 740, 700 cm-1. Anal. Calcd for C36H54O3Si2: C, 73.16;
H, 9.21. Found: C, 73.20; H, 9.38.
1-(tert-Butyldimethylsilyl)-7-(trimethylsilyl)-1,6-heptadiyne (26).
1H NMR δ 0.08 (s, 6 H), 0.14 (s, 9 H), 0.92 (s, 9 H), 1.73 (quintet, J
) 7.7 Hz, 2 H), 2.35 (t, J ) 7.7 Hz, 4 H); 13C NMR δ -4.45, 0.13,
16.50, 18.99 (two carbons), 26.09, 27.78, 83.22, 85.09, 106.30, 106.81;
IR (neat) 2960, 2940, 2860, 2180, 1250, 840, 780 cm-1. Anal. Calcd
for C16H30Si2: C, 68.98; H, 10.85. Found: C, 68.63; H, 10.78.
1-[(E)-2-[(E)-(tert-Butyldimethylsilyl)methylene]cyclopentylidene]-
1-(trimethylsilyl)-4-phenyl-2-butanol (27). 1H NMR δ 0.12 (s, 3 H),
0.14 (s, 3 H), 0.24 (s, 9 H), 0.95 (s, 9 H), 1.64 (br s, 1 H, OH), 1.62-
1.80 (m, 2 H), 1.80 (m, 1 H), 2.11 (m, 1 H), 2.30-2.55 (m, 4 H), 2.65
(dt, J ) 5, 12 Hz, 1 H), 2.93 (dt, J ) 5, 12 Hz, 1 H), 5.05 (br d, J )
9.5 Hz, 1 H), 5.46 (t, J ) 2 Hz, 1 H), 7.15-7.32 (m, 5 H); 13C NMR
δ -4.66, -4.44, 2.17, 17.23, 23.36, 26.59, 32.85 (two carbons), 33.94,
39.29, 74.82, 124.58, 125.72, 128.29, 128.38, 140.44, 142.38, 153.25,
157.80; IR (neat) 3500 (OH), 3080, 3040, 2960, 2860, 1600, 1500,
1470, 1250, 1040, 840, 700 cm-1. Anal. Calcd for C25H42OSi2: C,
72.40; H, 10.21. Found: C, 72.48; H, 10.32. The assigned structure
was verified by the selective desilylation of the trimethylsilyl group
with a catalytic amount of a base (vide infra).
Desilylation of the Trimethylsilyl Group of 27 (eq 4). 1-[(E)-2-
[(E)-(tert-Butyldimethylsilyl)methylene]cyclopentylidene]-4-phenyl-
2-butanol. Treatment of 27 with a catalytic amount of KH in THF at
room temperature for 10 min14 afforded the silyl ether, which was
dissolved in ether and aqueous 1 N HCl. This heterogeneous mixture
was stirred vigorously at room temperature for 45 min to afford the
title compound (65%) after purification on silica gel (hexanes-ether).
1H NMR δ 0.09 (s, 6 H), 0.90 (s, 9 H), 1.58 (br s, 1 H, OH), 1.69
(quintet, J ) 7.5 Hz, 2 H), 1.89 (m, 2 H), 2.36 (dt, J ) 1.5, 7.5 Hz, 2
H), 2.44 (dt, J ) 2, 7.5 Hz, 2 H), 2.70 (ddd, J ) 7, 8, 14 Hz, 1 H),
2.81 (ddd, J ) 7, 12, 14 Hz, 1 H), 4.75 (dt, J ) 5, 7 Hz, 1 H), 5.50 (d,
J ) 7.6 Hz, 1 H), 5.73 (t, J ) 1.5 Hz, 1 H), 7.15-7.34 (m, 5 H).
Typical Procedure for the Iodinolysis of the Intermediate
Oxatitanacycle such as 19. 1-[(E)-2-[(Z)-Iodo(phenyl)methylene]-
cyclohexylidene]-1-(trimethylsilyl)-4-phenyl-2-butanol (22). The above
reaction was repeated. In place of the aqueous workup (1 N HCl), the
solution was cooled to -78 °C and I2 (120 mg, 0.472 mmol) in 0.3
mL of THF was rapidly added under vigorous stirring. The solution
was rapidly warmed to 0 °C and stirred at this temperature for 30 min.
Additional ether (1 mL) was added to make the reaction mixture fluid.
After stirring for another 20 min, the reaction was terminated by the
addition of 1 N HCl at 0 °C. The organic layer was separated, washed
successively with aqueous NaHCO3 solution and Na2S2O3 solution,
dried (Na2SO4), and concentrated to an oil, purification of which by
silica gel chromatography (hexanes-ether) afforded the title compound
(38 mg, 62%) as an oil. 1H NMR δ 0.29 (s, 9 H), 1.26 (br s, 1 H, OH),
1.35-1.65 (m, 2 H), 1.73 (m, 1 H), 1.90-2.10 (m, 3 H), 2.22 (dt, J )
4.6, 11.5 Hz, 1 H), 2.40 (m, 1 H), 2.60 (br d, J ) 11 Hz, 1 H), 2.76
(m, 2 H), 2.94 (ddd, J ) 4.5, 8.5, 11.5 Hz, 1 H), 4.61 (dd, J ) 1.7,
10.5 Hz, 1 H), 7.12-7.36 (m, 10 H); 13C NMR δ 2.24, 29.45 (two
carbons), 33.87, 36.47, 36.60, 38.05, 75.89, 92.77, 125.71, 127.70,
128.24, 128.37, 128.69, 128.77, 134.63, 142.36, 143.34, 152.39, 156.78;
IR (neat) 3500 (OH), 3080, 3040, 2940, 2860, 1600, 1500, 1450, 1250,
1040, 850, 750, 700 cm-1. A structural confirmation was made by the
following iodine/lithium exchange reaction with t-BuLi. Treatment of
the iodide 22 with 3.5 equiv of t-BuLi (1.7 M solution in pentane) in
ether at -78 °C f -25 °C afforded the dehalogenated product 20 in
96% yield. Its spectroscopic properties and mobility on TLC were
identical with those of an authentic sample given above.
4,4-Bis(benzyloxymethyl)-1,7-bis(trimethylsilyl)-1,6-heptadiyne
1-[(E)-2-[(E)-Benzylidene]cyclohexylidene]-3-phenyl-1-(trimeth-
ylsilyl)-2-butanol (28). Major Isomer. 1H NMR δ 0.33 (s, 9 H), 1.34
(d, J ) 7 Hz, 1 H), 1.47 (br s, 1 H, OH), 1.3-1.72 (m, 4 H), 2.00 (m,
1 H), 2.50 (m, 3 H), 3.02 (dt, J ) 9, 7 Hz, 1 H), 4.94 (d, J ) 9 Hz, 1
H), 6.00 (br s, 1 H), 7.09-7.40 (m, 10 H); IR (neat) 3580 (OH), 3480
(OH), 3080, 3060, 3025, 2960, 2925, 2855, 1600, 1580, 1490, 1450,
1250, 1005, 990, 850, 840, 760, 735, 700 cm-1 for a 2:1 mixture of
the diastereoisomers. Anal. Calcd for C26H34OSi: C, 79.94; H, 8.77.
Found: C, 79.98; H, 8.93 for a 2:1 mixture of the diastereoisomers.
1
(23). H NMR δ 0.12 (s, 18 H), 2.44 (s, 4 H), 3.49 (s, 4 H), 4.51 (s,
4 H), 7.20-7.40 (m, 10 H); 13C NMR δ 0.15, 23.61, 42.31 (quaternary
carbon), 71.57, 73.49, 86.85, 103.89, 127.37 (two types of carbons),
128.26, 138.73; IR (neat) 3080, 3040, 2960, 2910, 2860, 2180, 1460,
1370, 1250, 1100, 1040, 850, 760, 740, 700 cm-1. Anal. Calcd for
C29H40O2Si2: C, 73.05; H, 8.46. Found: C, 72.94; H, 8.62.
1-[(E)-2-[(E)-(Trimethylsilyl)methylene]-4,4-bis(benzyloxymeth-
1
yl)cyclopentylidene]-1-(trimethylsilyl)-4-phenyl-2-butanol (24). H
NMR δ 0.18 (s, 9 H), 0.24 (s, 9 H), 1.60 (br s, 1 H, OH), 1.80 (m, 1
H), 2.11 (m, 1 H), 2.28 (dd, J ) 1.6, 15 Hz, 1 H), 2.29 (d, J ) 15 Hz,
1 H), 2.41 (dd, J ) 1.6, 15 Hz, 1 H), 2.49 (d, J ) 15 Hz, 1 H), 2.66
(m, 1 H), 2.88 (m, 1 H), 3.35 (d, J ) 8 Hz, 1 H), 3.36 (d, J ) 8 Hz,
1 H), 3.39 (d, J ) 8 Hz, 1 H), 3.43 (d, J ) 8 Hz, 1 H), 4.49 (d, J )
13 Hz, 1 H), 4.54 (s, 2 H), 4.56 (d, J ) 13 Hz, 1 H), 4.96 (dd, J ) 1.5,
9.6 Hz, 1 H), 5.41 (t, J ) 1.6 Hz, 1 H), 7.2-7.4 (m, 15 H); 13C NMR
δ -0.28, 1.98, 32.69, 38.48, 39.20, 39.50, 44.23 (quaternary carbon),
73.14, 73.18, 73.30, 73.70, 74.67, 125.75, 127.37, 127.42, 127.49,
128.14, 128.22, 128.36, 128.40, 138.71 (two peaks), 141.57, 142.26,
151.43, 155.64. Peaks in the region between δ 127.37 and 128.40 ppm
may include more than two types of carbons. IR (neat) 3570 (OH),
3100, 3080, 3040, 2950, 2860, 1600, 1500, 1460, 1370, 1250, 1100,
850, 750, 700 cm-1. Anal. Calcd for C38H52O3Si2: C, 74.46; H, 8.55.
Found: C, 74.49; H, 8.41.
1
Minor Isomer. Characteristic peaks of the H NMR spectrum are
shown: δ 0.37 (s, 9 H), 1.16 (d, J ) 7 Hz, 3 H), 6.34 (s, 1 H).
1-(Trimethylsilyl)-1,7-tridecadiyne (29). 1H NMR δ 0.14 (s, 9 H),
0.88 (t, J ) 7 Hz, 3 H), 1.31 (m, 4 H), 1.46 (quintet, J ) 7 Hz, 2 H),
1.58 (m, 4 H), 2.14 (m, 4 H), 2.24 (t, J ) 7 Hz, 2 H); 13C NMR δ
0.15, 13.97, 18.30, 18.72, 19.43, 22.21, 27.75, 28.21, 28.83, 31.08,
79.58, 80.60, 84.52, 107.20; IR (neat) 2940, 2860, 2180, 1460, 1250,
1050, 850, 760 cm-1. Anal. Calcd for C16H28Si: C, 77.34; H, 11.36.
Found: C, 76.92; H, 11.38.
1-[(E)-2-[(E)-Hexylidene]cyclohexylidene]-1-(trimethylsilyl)-2-de-
1
canol (30). H NMR δ 0.21 (s, 9 H), 0.85 (t, J ) 7 Hz, 3 H), 0.87 (t,
J ) 7 Hz, 3 H), 1.20-1.55 (m, 20 H), 1.55-1.75 (m, 5 H), 2.03 (q, J
) 7 Hz, 2 H), 2.20 (br m, 2 H), 2.33 (br m, 2 H), 4.61 (dd, J ) 4.8,
7.9 Hz, 1 H), 5.04 (t, J ) 7 Hz, 1 H). The following NOE study
confirmed the assigned stereochemistry. Irradiation of the proton at δ
4.61 ppm (CHOH) showed a 7% enhancement to that at δ 5.04 ppm
(vinylic H). Alternatively, irradiation of the proton at δ 5.04 ppm
(vinylic H) showed a 6% enhancement to that at δ 4.61 ppm (CHOH).
13C NMR δ 2.51, 14.04, 22.56, 22.67, 26.71, 27.30, 28.05, 28.92, 29.29,
29.63, 29.68 (may involve more than two carbons), 29.71, 30.90, 31.60,
31.90, 37.65, 37.85, 75.28, 124.89, 134.82, 141.41, 155.96; IR (neat)
3450 (OH), 2920, 2850, 1450, 1240, 840 cm-1. Anal. Calcd for C25H48-
OSi: C, 76.46; H, 12.32. Found: C, 76.06; H, 12.33.
2-[(E)-2-[(E)-(Trimethylsilyl)methylene]-4,4-bis(benzyloxymeth-
yl)cyclopentylidene]-2-(trimethylsilyl)-1-cyclohexylethanol (25). 1H
NMR δ 0.13 (s, 9 H), 0.20 (s, 9 H), 0.8-1.8 (m, 11 H), 2.07 (br d, J
) 13 Hz, 1 H), 2.24 (d, J ) 15 Hz, 1 H), 2.31 (d, J ) 15 Hz, 1 H),
2.32 (d, J ) 15 Hz, 1 H), 2.38 (d, J ) 15 Hz, 1 H), 3.35 (s, 2 H), 3.35
(d, J ) 8.5 Hz, 1 H), 3.37 (d, J ) 8.5 Hz, 1 H), 4.45 (d, J ) 12 Hz,
2 H), 4.51 (d, J ) 12 Hz, 2 H), 4.72 (d, J ) 7.7 Hz, 1 H), 5.64 (s, 1
H), 7.22-7.35 (m, 10 H). The following NOE study confirmed the
assigned stereochemistry. Irradiation of the proton at δ 4.72 ppm
(CHOH) showed a 20% enhancement at the peak of δ 5.64 ppm (vinylic
H). 13C NMR δ -0.26, 1.89, 26.09, 26.25, 26.62, 30.09, 30.41, 38.39,
39.63, 43.17, 44.15 (quaternary carbon), 73.19, 73.23, 73.54, 73.64,
78.26, 127.38, 127.44, 127.50, 128.24, 138.73, 138.76, 139.21, 154.43,
155.34; IR (neat) 3500 (OH), 3040, 2940, 2850, 1600, 1460, 1360,
N-Benzyl-N-(3-phenylpropargyl)-N-[4-(trimethylsilyl)-3-butynyl]-
1
amine (31). H NMR δ 0.15 (s, 9 H), 2.48 (t, J ) 7.7 Hz, 2 H), 2.85
(t, J ) 7 Hz, 2 H), 3.56 (s, 2 H). 3.74 (s, 2 H), 7.22-7.51 (m, 10 H);
13C NMR δ 0.11, 19.38, 42.42, 52.42, 57.92, 84.44, 85.40, 85.54,
105.51, 123.32, 127.11, 127.99, 128.26 (two types of carbons), 129.00,
131.74, 138.76; IR (neat) 3080, 3040, 2970, 2850, 2200, 1690, 1500,

1254 J. Am. Chem. Soc., Vol. 121, No. 6, 1999
Urabe and Sato
1460, 1340, 1260, 1130, 1040, 850, 760, 700 cm-1. Anal. Calcd for
C23H27NSi: N, 4.05. Found: N, 3.72.
(O-i-Pr)4 (0.041 mL, 0.140 mmol) in 1.5 mL of Et2O was added
i-PrMgCl (1.66 M in ether, 0.186 mL, 0.308 mmol) dropwise at -78
°C under argon. After stirring for 30 min, the solution was warmed to
-50 °C over 30 min and kept at this temperature for 2 h. After another
portion of i-PrMgCl (1.66 M in ether, 0.084 mL, 0.140 mmol) was
added at the same temperature, the dark-brown mixture was further
stirred at -50 °C for 2 h. Pivalaldehyde (0.049 mL, 0.448 mmol) was
then added, and the light-brown reaction mixture was stirred at -50
°C for 5 min and was rapidly allowed to warm to 0 °C. After the
solution was stirred at 0 °C for an additional 30 min, the reaction was
terminated by the addition of aqueous 1 N HCl. The organic layer was
separated, washed with aqueous NaHCO3 solution, dried (Na2SO4), and
concentrated to an oil, which was chromatographed on silica gel
(hexanes-ether) to afford the title compound (14.5 mg, 49%) as a
colorless oil. 1H NMR δ 0.89 (t, J ) 6.8 Hz, 3 H), 0.95 (s, 9 H), 1.24-
1.43 (m, 8 H), 1.69 (m, 1 H), 1.82 (m, 1 H), 1.88 (d, J ) 3.7 Hz, 1 H,
OH), 2.05 (q, J ) 7.3 Hz, 2 H), 2.36 (m, 2 H), 2.75 (br t, J ) 7.0 Hz,
2 H), 3.00 (dd, J ) 3.7, 7.0 Hz, 1 H), 4.81 (s, 1 H), 5.47 (s, 1 H), 5.88
(tt, J ) 2.5, 7.3 Hz, 1 H); 13C NMR δ 13.97, 22.52, 26.11, 27.54,
29.03, 29.14, 29.66, 30.53, 31.67, 35.90 (quaternary carbon), 47.64,
78.21, 105.20, 122.31, 139.25, 150.91; IR (neat) 3560 (OH), 3080, 2960,
2925, 2870, 2860, 1620, 1480, 1460, 1395, 1360, 1285, 1235, 1080,
1010, 880 cm-1. Anal. Calcd for C18H32O: C, 81.75; H, 12.20. Found:
C, 81.57; H, 12.24.
N-Benzyl-3-[(E)-benzylidene)]-4-[(E)-1-(trimethylsilyl)-2-hydroxy-
1
decylidene]piperidine (32). H NMR δ 0.26 (s, 9 H), 0.86 (t, J ) 7
Hz, 3 H), 1.23 (br m, 10 H), 1.44 (br s, 1 H, OH), 1.52 (m, 2 H), 1.70
(br m, 2 H), 2.57 (br m, 2 H), 2.70 (br m, 2 H), 3.25 (br m, 2 H), 3.50
(s, 2 H), 4.82 (dd, J ) 5.1, 6.9 Hz, 1 H), 6.31 (s, 1 H), 7.10 (d, J ) 7.5
Hz, 2 H), 7.15-7.30 (m, 8 H). Irradiation of the proton at δ 4.82 ppm
(CHOH) showed a 9% NOE enhancement to that at δ 6.31 ppm (vinylic
H), which confirmed the stereochemistry. 13C NMR δ 2.61, 14.06,
22.66, 26.67, 29.25, 29.59 (two carbons), 31.84, 35.79, 37.67, 55.11,
55.73, 61.99, 74.89, 126.66, 127.03, 127.33, 128.10 (two types of
carbons), 128.93, 129.21, 136.71, 137.91, 138.19, 138.72, 151.73; IR
(neat) 3450 (OH), 3080, 3040, 2950, 2860, 1480, 1260, 850, 740, 705
cm-1. Anal. Calcd for C32H47ONSi: N, 2.86. Found: N, 2.50.
1
1-[(E)-Heptylidene]-2-methylcyclopentane (33). H NMR δ 0.88
(t, J ) 7 Hz, 3 H), 1.04 (d, J ) 7 Hz, 3 H), 1.05-1.40 (m, 9 H), 1.52
(m, 1 H), 1.70 (m, 1 H), 1.84 (m, 1 H), 1.95 (br q, J ) 7 Hz, 2 H),
2.13-2.37, (m, 3 H), 5.11 (tt, J ) 2.1, 7 Hz, 1 H).
(RS)-[(SR)-3-[(E)-Heptylidene]-2-methylenecyclopentyl](phenyl)-
1
methanol (34). H NMR δ 0.89 (t, J ) 7 Hz, 3 H), 1.24-1.48 (m, 8
H), 1.48-1.64 (m, 2 H), 2.06 (q, J ) 7.1 Hz, 2 H), 2.31 (m, 2 H), 2.40
(br s, 1 H, OH), 2.82 (t-like m, 1 H), 4.32 (d, J ) 9.2 Hz, 1 H), 5.05
(s, 1 H), 5.43 (s, 1 H), 5.94 (tt, J ) 2.6, 7.6 Hz, 1 H), 7.22-7.40 (m,
5 H). The following NOE study confirmed the assigned stereochemistry.
Irradiation of the peak at δ 5.43 ppm (endo-CdCH2) showed 31% and
13% enhancement to the protons at δ 5.05 (exo-CdCH2) and δ 5.94
ppm (CdCHC6H13). Irradiation of the peak at δ 5.05 ppm (exo-Cd
CH2) showed 2.4%, 4%, 31%, and -3% enhancement to the protons
at δ 2.40 (OH), δ 2.82 CHCH(OH)), δ 5.43 (endo-CdCH2), and δ
5.94 ppm (CdCHC6H13). Irradiation of the peak at δ 5.94 ppm (Cd
CHC6H13) showed 2%, -1.4%, and 6% enhancement to the protons at
δ 2.06 (allylic CH2 of C6H13), δ 5.05 (exo-CdCH2), and δ 5.43 ppm
(endo-CdCH2). Irradiation of the peak at δ 2.40 ppm (OH) showed
6.5% and 2% enhancement to the protons at δ 4.32 (CH(OH)) and δ
5.05 ppm (exo-CdCH2). Irradiation of the peak at δ 2.82 ppm (CHCH-
(OH)) showed 2% and 4% enhancement to the protons at δ 5.05 (exo-
CdCH2) and δ 7.35 ppm (o-Ph). 13C NMR δ 13.99, 22.53, 26.26, 27.43,
29.03, 29.14, 29.60, 31.68, 53.67, 74.93, 101.14, 122.78, 127.19, 127.77,
128.39, 139.04, 142.66, 151.09; IR (neat) 3400 (OH), 3070, 3030, 2960,
2920, 2860, 1620, 1495, 1455, 1380, 1190, 1040, 1020, 885, 760, 700
cm-1. Anal. Calcd for C20H28O: C, 84.45; H, 9.92. Found: C, 84.41;
H, 10.14.
9-[(tert-Butyl)dimethylsiloxy]-1-nonen-6-yne (44). 1H NMR δ 0.06
(s, 6 H), 0.89 (s, 9 H), 1.56 (quintet, J ) 7 Hz, 2 H), 2.15 (m, 4 H),
2.37 (tt, J ) 2.3, 7.2 Hz, 2 H), 3.69 (t, J ) 7.5 Hz, 2 H), 4.97 (d, J )
11 Hz, 1 H), 5.03 (d, J ) 17 Hz, 1 H), 5.89 (ddt, J ) 11, 17, 7.5 Hz,
1 H); 13C NMR δ -5.42, 18.06, 18.24 (quaternary carbon), 23.08, 25.80,
28.06, 32.71, 62.36, 77.22, 81.01, 115.01, 138.16; IR (neat) 3080, 2925,
2860, 1640, 1470, 1460, 1255, 1105, 915, 840, 775 cm-1. Anal. Calcd
for C15H28OSi: C, 71.36; H, 11.18. Found: C, 71.01; H, 10.90.
(RS)-[(SR)-3-[(E)-3-[(tert-Butyl)dimethylsiloxy]propylidene]-2-
methylenecyclopentyl](2-furyl)methanol (45). 1H NMR δ 0.06 (s, 6
H), 0.90 (s, 9 H), 1.51 (m, 1 H), 1.74 (dq, J ) 13, 7.6 Hz, 1 H), 2.26-
2.40 (m, 5 H), 3.06 (t-like m, 1 H), 3.66 (t, J ) 7 Hz, 2 H), 4.44 (dd,
J ) 3.6, 8.8 Hz, 1 H), 5.00 (s, 1 H), 5.43 (s, 1 H), 5.92 (tt, J ) 2.7, 7.6
Hz, 1 H), 6.28 (d, J ) 3.2 Hz, 1 H), 6.34 (dd, J ) 1.8, 3.2 Hz, 1 H),
7.40 (dd, J ) 0.8, 1.8 Hz, 1 H); 13C NMR δ -5.43, 18.24 (quaternary
carbon), 25.82, 26.34, 27.61, 33.34, 50.67, 62.45, 68.66, 104.96, 107.45,
110.16, 118.45, 140.84, 142.23, 149.93, 155.00; IR (neat) 3420 (OH),
2960, 2930, 2890, 2860, 1620, 1500, 1470, 1460, 1380, 1360, 1255,
1150, 1100, 1010, 940, 920, 840, 810, 780, 735 cm-1. Anal. Calcd for
C20H32O3Si: C, 68.92; H, 9.25. Found: C, 68.60; H, 8.97.
1-[(E)-Heptylidene]-2-methylenecyclopentane (35). Characteristic
1
peaks of the H NMR spectrum: δ 4.76 (s, 1 H), 5.21 (s, 1 H), 5.86
(tt, J ) 2.5, 7.5 Hz, 1 H).
Typical Procedure for the Copper-Mediated Allylation of
Titanabicycles. 1,1-Bis(benzyloxymethyl)-3-[(E)-1-(trimethylsilyl)-
3-butenylidene]-4-methylcyclopentane (48). To a stirred mixture of
4,4-bis(benzyloxymethyl)-1-(trimethylsilyl)-6-hepten-1-yne (2) (30 mg,
0.074 mmol) and Ti(O-i-Pr)4 (0.027 mL, 0.092 mmol) in 1 mL of Et2O
was added i-PrMgCl (1.60 M in ether, 0.127 mL, 0.203 mmol) dropwise
at -78 °C under argon. After stirring for 30 min, the solution was
warmed to -50 °C over 30 min and kept at this temperature for 2 h.
Then a THF solution of Li2Cu(CN)Cl2 (0.5 M in THF, 0.148 mL, 0.074
mmol) was added, followed 10 min later by allyl bromide (2 M solution
in hexane, 0.044 mL, 0.089 mmol) at the same temperature. After the
heterogeneous mixture was stirred at -50 °C for 3 h, the reaction was
terminated by the addition of aqueous 1 N HCl. The organic layer was
separated, washed with aqueous NaHCO3 solution, dried (Na2SO4), and
(RS)-[(SR)-3-[(E)-Heptylidene]-2-methylenecyclopentyl](2-furyl)-
1
methanol (41). H NMR δ 0.88 (t, J ) 7 Hz, 3 H), 1.17-1.44 (m, 8
H), 1.51 (m, 1 H), 1.73 (m, 1 H), 2.06 (q, J ) 7.4 Hz, 2 H), 2.32 (d,
J ) 3.7 Hz, 1 H, OH), 2.32 (m, 2 H), 3.05 (t-like m, 1 H), 4.44 (dd,
J ) 3.7, 8.9 Hz, 1 H), 4.97 (s, 1 H), 5.42 (s, 1 H), 5.92 (tt, J ) 2.7, 7.4
Hz, 1 H), 6.28 (d, J ) 3.2 Hz, 1 H), 6.37 (dd, J ) 2.1, 3.2 Hz, 1 H),
7.40 (dd, J ) 0.8, 2.1 Hz, 1 H); 13C NMR δ 13.99, 22.53, 26.38, 27.48,
29.03, 29.14, 29.60, 31.67, 50.74, 68.65, 104.39, 107.44, 110.16, 122.76,
138.95, 142.22, 150.16, 155.06; IR (neat) 3420 (OH), 3120, 3080, 2960,
2920, 2860, 1620, 1505, 1460, 1380, 1150, 1040, 1010, 885, 810, 735
cm-1. Anal. Calcd for C18H26O2: C, 78.79; H, 9.55. Found: C, 78.78;
H, 9.62.
(RS)-[(RS)-3-[(E)-Heptylidene]-2-methylenecyclopentyl](cyclohexyl)-
methanol (42). 1H NMR δ 0.88 (t, J ) 7 Hz, 3 H), 1.10-1.85 (m, 19
H), 1.68 (d, J ) 3.5 Hz, 1 H, OH), 2.05 (q, J ) 7.2 Hz, 2 H), 2.34
(t-like m, 2 H), 2.65 (t-like m, 1 H), 3.14 (dt, J ) 8.6, 3.5 Hz, 1 H),
4.91 (s, 1 H), 5.36 (s, 1 H), 5.87 (tt, J ) 2.5, 7.6 Hz, 1 H); 13C NMR
δ 13.98, 22.53, 25.66, 26.28, 26.48, 26.68, 26.74, 27.71, 29.03, 29.17,
29.57, 31.00, 31.68, 40.55, 48.58, 75.78, 103.51, 122.08, 139.57, 151.42;
IR (neat) 3480 (OH), 3080, 2920, 2855, 1620, 1450, 1380, 1260, 1100,
985, 890 cm-1. Anal. Calcd for C20H34O: C, 82.70; H, 11.80. Found:
C, 82.76; H, 11.96.
Typical Procedure for the Cyclization and Dehydrogenation of
Enynes Followed by the Addition to Aldehydes. (RS)-1-[(SR)-3-[(E)-
Heptylidene]-2-methylenecyclopentyl]-2,2-dimethyl-1-propanol (43).
To a mixture of 1-tridecen-6-yne (10) (20 mg, 0.112 mmol) and Ti-
1
concentrated to an oil, H NMR analysis of which showed the nearly
quantitative formation of the title compound and less than 5% each of
the (possible) regioisomer and the bis-protonated 55. Purification on
silica gel (hexanes-ether) afforded the title compound (27 mg, 82%)
1
of the same composition as above as a colorless oil. H NMR δ 0.08
(s, 9 H), 1.03 (d, J ) 7.5 Hz, 3 H), 1.25 (dd, J ) 6, 14 Hz, 1 H), 1.84
(dd, J ) 8, 14 Hz, 1 H), 2.22 (d, J ) 15 Hz, 1 H), 2.46 (d, J ) 15 Hz,
1 H), 2.75 (m, 1 H), 2.79 (dd, J ) 5.5, 15 Hz, 1 H), 2.93 (dd, J ) 5.5,
15 Hz, 1 H), 3.18 (d, J ) 8 Hz, 1 H), 3.26 (d, J ) 8 Hz, 1 H), 3.40 (d,
J ) 8 Hz, 1 H), 3.54 (d, J ) 8 Hz, 1 H), 4.40 (d, J ) 12 Hz, 1 H),
4.50 (d, J ) 12 Hz, 1 H), 4.54 (s, 2 H), 4.90 (d, J ) 18 Hz, 1 H), 4.92
(d, J ) 9.5 Hz, 1 H), 5.77 (ddt, J ) 9.5, 18, 5.5 Hz, 1 H), 7.22-7.36

Allylation of Bicyclic Titanacyclopentenes
J. Am. Chem. Soc., Vol. 121, No. 6, 1999 1255
(m, 10 H). Decoupling of the proton at δ 5.77 ppm (CHdCH2) changes
the following peaks: δ 2.79 ppm (dd, J ) 5.5, 15 Hz, 1 H, bis-allylic
H) f (d, J ) 15 Hz); δ 2.93 ppm (dd, J ) 5.5, 15 Hz, 1 H, bis-allylic
H) f (d, J ) 15 Hz); δ 4.90 ppm (d, J ) 18 Hz, 1 H, CHdCH2) and
δ 4.92 ppm (d, J ) 9.5 Hz, 1 H, CHdCH2) f δ 4.91 ppm (br s). The
following NOE study confirmed the assigned stereochemistry. Irradia-
tion of the peak at δ 1.03 ppm (cyclopentyl Me) showed a 9%
enhancement to the proton at δ 2.75 ppm (CHMe). Irradiation of the
peak at δ 2.93 ppm (bis-allylic H) showed 2% and 5% enhancement
to the protons at δ 1.03 (cyclopentyl Me) and δ 5.77 ppm (CHdCH2).
13C NMR δ 0.18, 22.79, 35.11, 35.89, 38.80, 39.45, 47.01 (quaternary
carbon), 72.43, 73.19, 73.23, 75.06, 114.23, 127.26, 127.34, 127.48,
128.17, 128.22, 138.41, 138.75, 138.83, 139.04, 159.16. The peaks in
the region between δ 127.26 and 128.22 ppm may contain two types
of aromatic carbons. IR (neat) 3070, 3030, 2955, 2920, 2895, 2860,
1635, 1620, 1495, 1455, 1360, 1250, 1100, 1030, 910, 850, 840, 735,
700 cm-1. Anal. Calcd for C29H40O2Si: C, 77.62; H, 8.99. Found: C,
77.62; H, 9.10.
A 6:4 Mixture of 2-[(E)-(Trimethylsilyl)methylene]-1-[(E)-1-
phenyl-3-butenylidene]cyclohexane (51) and 2-[(E)-Benzylidene]-
1-[(E)-1-(trimethylsilyl)-3-butenylidene]cyclohexane (52). 1H NMR
δ 0.17 (s, 9 H, 51), 0.19 (s, 9 H, 52), 1.50-1.75 (m, 4 H, 51 + 52),
2.10 (t, J ) 6 Hz, 2 H, 51), 2.36 (t, J ) 6 Hz, 2 H, 51), 2.43 (m, 4 H,
52), 3.04 (dt, J ) 6, 2 Hz, 2 H, 52), 3.20 (d, J ) 7 Hz, 2 H, 51), 4.85
(d, J ) 11 Hz, 1 H, 51), 4.85 (d, J ) 17 Hz, 1 H, 51), 4.95 (d, J ) 17
Hz, 1 H, 52), 4.98 (d, J ) 9 Hz, 1 H, 52), 5.38 (s, 1 H, 51), 5.65 (m,
1 H, 51), 5.87 (m, 1 H, 52), 6.28 (s, 1 H, 52), 7.10-7.35 (m, 5 H, 51
+ 52); IR (neat) 3080, 2955, 2925, 2855, 1600, 1440, 1250, 910, 850,
840, 700 cm-1 for a 6:4 mixture of 51 and 52. Anal. Calcd for C20H28-
Si: C, 81.01; H, 9.52. Found: C, 81.07; H, 9.75 for a 6:4 mixture of
51 and 52.
1-[(Z)-1-Nonen-4,4-ylidene]-2-[(E)-(trimethylsilyl)methylene]cy-
clohexane (53). 1H NMR δ 0.09 (s, 9 H), 0.87 (t, J ) 7 Hz, 3 H), 1.28
(br m, 6 H), 1.62 (br m, 4 H), 2.00 (t, J ) 7.5 Hz, 2 H), 2.22 (m, 4 H),
2.87 (d, J ) 6.6 Hz, 2 H), 4.95 (d, J ) 10.5 Hz, 1 H), 4.97 (d, J ) 17
Hz, 1 H), 5.13 (s, 1 H), 5.75 (ddt, J ) 10.5, 17, 7 Hz, 1 H). The
following NOE study confirmed the assigned stereochemistry. Irradia-
tion of the peak at δ 2.87 ppm (bis-allylic CH2) showed a 4% enhance-
ment to the proton at δ 5.13 ppm (CdCHSiMe3). 13C NMR δ 0.34,
14.07, 22.61, 28.05, 28.67, 28.80, 30.62, 32.06, 32.14, 36.51, 37.73,
114.70, 123.11, 128.57, 138.51, 140.86, 159.36; IR (neat) 3080, 2960,
2925, 2855, 1635, 1600, 1440, 1250, 910, 855 cm-1. Anal. Calcd for
C19H34Si: C, 78.54; H, 11.79. Found: C, 78.32; H, 11.95.
The Possible Minor Regioisomer. A characteristic peak of the 1H
NMR spectrum: δ 5.01 (br q, J ) 1.5 Hz, 1 H).
1
1-(Trimethylsilyl)-7-octen-1-yne (49). H NMR δ 0.13 (s, 9 H),
1.50 (m, 4 H), 2.06 (q, J ) 7 Hz, 2 H), 2.23 (t, J ) 7 Hz, 2 H), 4.95
(d, J ) 9 Hz, 1 H), 5.01 (d, J ) 17 Hz, 1 H), 5.80 (ddt, J ) 9, 17, 7
Hz, 1 H); 13C NMR δ 0.17, 19.71, 28.01, 28.05, 33.17, 84.44, 107.44,
114.50, 138.61; IR (neat) 3080, 2960, 2940, 2860, 2175, 1640, 1430,
1250, 990, 915, 840, 760, 700, 640 cm-1. Anal. Calcd for C11H20Si:
C, 73.25; H, 11.18. Found: C, 73.13; H, 11.14.
1-Methyl-2-[(E)-1-(trimethylsilyl)-3-butenylidene]cyclohexane (50).
1H NMR δ 0.10 (s, 9 H), 1.04 (d, J ) 7.5 Hz, 3 H), 1.24 (m, 1 H),
1.40-1.65 (m, 4 H), 1.79 (br d, J ) 12 Hz, 1 H), 2.17 (dt, J ) 5, 13
Hz, 1 H), 2.39 (br d, J ) 13 Hz, 1 H), 2.75-2.95 (m, 3 H), 4.93 (dt,
J ) 11, 2 Hz, 1 H), 4.94 (dt, J ) 16.7, 2 Hz, 1 H), 5.81 (m, 1 H); IR
(neat) 3080, 2960, 2920, 2860, 1635, 1600, 1450, 1250, 990, 910, 855,
835, 760, 685 cm-1. Anal. Calcd for C14H26Si: C, 75.59; H, 11.78.
Found: C, 75.22; H, 11.81.
1-[(Z)-1-Nonen-4,4-ylidene]-2-[(E)-(trimethylsilyl)(deuterio)meth-
ylene]cyclohexane (53-d1). The 1H NMR peak at δ 5.13 ppm (s, 1 H)
of 53 almost completely disappeared.
1-[(E)-Hexylidene]-2-[(E)-1-(trimethylsilyl)-3-butenylidene]cyclo-
1
hexane (54). A characteristic peak of the H NMR spectrum: δ 2.93
(dt, J ) 5.4, 2 Hz, 2 H).
Acknowledgment. We thank the Ministry of Education,
Science, Sports and Culture (Japan) for financial support.
JA982501E