New formulas for organozincate chemistry

Article abstract of DOI:10.1021/ja973855t

As a new type of zincate, we designed various new organozinc derivatives, Me₃Zn(R)Li₂ (R = Me, CN, SCN), which could be prepared in situ from lithium trimethylzincate and anion species such as methyllithium, lithium cyanide, and lithium thiocyanate. We investigated the reactivities of these zincates toward the halogen (or tellurium)-zinc exchange, Michael addition, carbozincation, and epoxide ring opening reactions. On the basis of their excellent chemical yields and chemoselectivities, these species were considered to be differentiated from ordinary triorganozincates, R₃ZnLi. We also discuss the structure of the newly designed zincates using ¹H NMR/Raman/in situ FTIR/extended X-ray absorption the structure (EXAFS) spectroscopic and the density functional theory (DFT) theoretical studies. All results strongly support the fact that these newly designed zincates are a new category of zincate species. This observation is also identical with the fact that newly designed zincates have a higher and unique reactivity compared to the conventional triorganozincates.

Full text of DOI:10.1021/ja973855t

4934
J. Am. Chem. Soc. 1998, 120, 4934-4946
New Formulas for Organozincate Chemistry
Masanobu Uchiyama,* Mitsuyoshi Kameda, Osamu Mishima, Nobuko Yokoyama,
Minako Koike, Yoshinori Kondo, and Takao Sakamoto*
Contribution from the Faculty of Pharmaceutical Sciences, Tohoku UniVersity, Aobayama, Aoba-ku,
Sendai 980-8578, Japan
ReceiVed NoVember 10, 1997
Abstract: As a new type of zincate, we designed various new organozinc derivatives, Me3Zn(R)Li2 (R ) Me,
CN, SCN), which could be prepared in situ from lithium trimethylzincate and anion species such as
methyllithium, lithium cyanide, and lithium thiocyanate. We investigated the reactivities of these zincates
toward the halogen (or tellurium)-zinc exchange, Michael addition, carbozincation, and epoxide ring opening
reactions. On the basis of their excellent chemical yields and chemoselectivities, these species were considered
to be differentiated from ordinary triorganozincates, R3ZnLi. We also discuss the structure of the newly designed
zincates using 1H NMR/Raman/in situ FTIR/extended X-ray absorption fine structure (EXAFS) spectroscopic
and the density-functional theory (DFT) theoretical studies. All results strongly support the fact that these
newly designed zincates are a new category of zincate species. This observation is also identical with the fact
that newly designed zincates have a higher and unique reactivity compared to the conventional triorganozincates.
Introduction
Chart 1. Ate Complexes
Organometallic reagents having Lewis acidity (vacant orbital)
often form complexes with anion species, such as carboanions,
alkoxy anions, and the like, to generate metallic anion complexes
defined as ate complexes (Chart 1).1 There have been many
experimental and theoretical studies on the structure and
reactivities of various ate complexes. Ate complexes, being
bimetallic compounds, are known to show unique reactivities
that metallic reagents themselves do not possess. For example,
while the most important classes of organozinc derivatives are
the organozinc halides (Reformatsky-type, symbolized as RZnX)
and diorganozincs (R2Zn), these organozinc reagents often have
poor reactivity without catalysts such as amino alcohols,
transition metals, etc. toward alkylation reaction of the carbonyl
compounds and the halogen-metal exchange reaction of alkyl
halides. However, triorganozincates (R3Zn- Metal+) are known
to proceed 1,4-conjugated addition reaction with R,â-unsaturated
carbonyl compounds,2 the metalation reaction of aromatic
halides3 or vinyl halides,4 and the reduction of the various
carbonyl compounds5 (Figure 1).
possessing Lewis basicity. The outer shell of the zinc atom in
a lithium trimethylzincate is filled with 16 electrons, and there
is a vacant orbital for an additional ligand to coordinate, which
could form a favorable 18 electron state (Figure 2). Therefore,
lithium trimethylzincate possibly forms further complexes with
anion species, such as MeLi, LiCN, LiSCN, and the like, to
generate tetracoordinated organozinc derivatives. However, the
reactivity of the tetraalkylzincates have never been well studied.
In this paper, we report the control of the reactivity of zincates
by the change in the coordination environment on the Zn, that
is, unique reactivities of “newly designed ate complexes” of
organozinc derivatives, symbolized as Me3Zn(R)Li2 (R ) Me,
CN, SCN), toward halogen (or tellurium)-zinc exchange, inter-
Lithium trimethylzincate, one of the triorganozincates, is a
complex arising from Me2Zn having Lewis acidity and MeLi
(1) (a) Wittig, G. Q. ReV. 1966, 191-210. (b) Tochtermann, W. Angew.
Chem., Int. Ed. Engl. 1966, 5, 351-375.
(2) (a) Isobe, M.; Kondo, S.; Nagasawa, N.; Goto, T. Chem. Lett. 1977,
679-682. (b) Tuckmantel, W.; Oshima, K.; Nozaki, H. Chem. Ber. 1986,
119, 1581-1593. (c) Jansen, J. F. G. A.; Ferringa, B. L. Tetrahedron Lett.
1988, 29, 3593-3596. (d) Kjonaas, R. A.; Hoffer, R. K. J. Org. Chem.
1988, 53, 4133-4135.
(3) (a) Kondo, Y.; Takazawa, N.; Yamazaki, C.; Sakamoto, T. J. Org.
Chem. 1994, 59, 4717-4718. (b) Kondo, Y; Matsudaira, T.; Sato, J.; Murata,
N.; Sakamoto, T. Angew. Chem., Int. Ed. Engl. 1996, 35, 736-738. (c)
Kondo, Y.; Takazawa, N.; Yoshida, A.; Sakamoto, T. J. Chem. Soc., Perkin
Trans. 1 1995, 1207-1208. (d) Kondo, Y.; Fujinami, M.; Uchiyama, M.;
Sakamoto, T. J. Chem. Soc., Perkin Trans. 1 1997, 799-800.
(4) (a) Harada, T.; Katsuhira, K.; Hattori, K.; Oku, A. J. Org. Chem.
1993, 58, 2958-2965. (b) Harada, T.; Katsuhira, K.; Hara, D.; Kotani, Y.;
Maejima, K.; Kaji, R.; Oku, A. J. Org. Chem. 1993, 58, 4897-4907.
(5) Uchiyama, M.; Furumoto, S.; Saito, M.; Kondo, Y.; Sakamoto, T. J.
Am. Chem. Soc. 1997, 119, 11425-11433.
Figure 1. Reactivities of triorganozincates.
S0002-7863(97)03855-9 CCC: $15.00 © 1998 American Chemical Society
Published on Web 05/12/1998

New Formulas for Organozincate Chemistry
J. Am. Chem. Soc., Vol. 120, No. 20, 1998 4935
Figure 2. Design of new ate complexes of organozinc derivatives.
Scheme 1. Preparations of New Ate Complexes of Organozinc Derivatives
Table 1. 1H NMR of Metal Reagents in THF (-20 °C)
and intramolecular epoxide ring opening, Michael addition, and
carbozincation reactions.6 We also discuss the structure and
the active species of the newly designed zincates using 1H NMR/
Raman/in situ FTIR/extended X-ray absorption fine structure
(EXAFS) spectroscopic and the density-functional theory (DFT)
theoretical studies.
entry
metal reagent
δ
Me (ppm)a
1
2
3
4
5
6
MeLi
MeMgBr
Me3Al
Me2Zn
Me3SiNCS
Me3SiCN
-1.96
-1.62
-0.82
-0.84
+0.40
+0.38
Results and Discussion
a The δ values are relative to â methylene proton (1.85 ppm) of
THF.
Design and Preparation of Newly Designed Ate Complexes
of Organozinc Derivatives. The preparation of newly designed
zincates was investigated (Scheme 1) and the 1H NMR spectra
of the zincates were obtained for the preliminary estimation of
MeLi in THF using the previously reported modified procedure.7
The methyl signal of Me4ZnLi2 in THF (-1.44 ppm) was
observed as a sharp singlet in the middle between the signals
of Me3ZnLi (-1.08 ppm) and MeLi (-1.96 ppm). Measure-
ment at -78 °C gave very similar results but with a slight high
field shift of each signal. The addition of one more equivalent
of MeLi to the Me4ZnLi2 solution showed a broad singlet signal
at -1.49 ppm at -20 °C which separated at -78 °C into two
signals corresponding to the signal of MeLi and that of Me4-
ZnLi2. The high field shift from the value of Me3ZnLi is
considered to indicate the more anionic character of the zincates.
Indeed, there are some reports of tetraalkylzincates,8 and X-ray
studies of the zincates which have disclosed that the crystal
1
the component of the zincate solution. First, the H NMR
spectra of the metal reagents were measured (Table 1). The
methyl signals of MeLi, MeMgBr, Me3Al, and Me2Zn in THF
(-20 °C) were observed as a sharp singlet at -1.96, -1.62,
-0.82, and -0.84 ppm, respectively. A high field shift from
the value of Me4Si (0.00 ppm) was considered to show the
anionic character of each metal reagent. Indeed, the order of
the high field shift value is nearly consistent with the order of
the reactivities of the metal reagents.
With this information, we estimated the possibility of the
formation and the reactivity of newly designed zincates using
1H NMR spectroscopy (Figure 3). Dilithium tetramethylzincate
was prepared by the reaction of zinc chloride with 4 equiv of
(7) (a) Hurd, D. T. J. Org. Chem. 1948, 13, 711-713. (b) Nast, R. Angew.
Chem. 1960, 72, 26-31. (c) Seitz, L. M.; Brown, T. L. J. Am. Chem. Soc.
1966, 88, 4140-4147. (d) Toppet, S.; Slinckx, G.; Smets, G. J. Organomet.
Chem. 1967, 9, 205-213. (e) Kaufmann, F.; Geraudelle, A.; Kaempf, B.;
Schue, F.; Deluzarche, A.; Maillard, A. J. Organomet. Chem. 1974, 71, 11-
15. (f) Chastrette, M.; Gauthier, R. J. Organomet. Chem. 1974, 71, 11-15.
(8) (a) Weiss, E.; Wolfrum, R. Chem. Ber. 1968, 101, 35-40. (b) Weiss,
E.; Plass, H. J. Organomet. Chem. 1968, 14, 21-31.
(6) (a) A part of the work was communicated in: Uchiyama, M.; Koike,
M.; Kameda, M.; Kondo, Y.; Sakamoto, T. J. Am. Chem. Soc. 1996, 118,
8733-8734. (b) More recently, “highly coordinated” zincates were used
as a reactive intermediates for asymmetric 1,2-migration reaction: McWil-
liams, J. C.; Armstrong, J. D., III; Zheng, N.; Bhupathy, M.; Volante, R.
P.; Reider, P. L. J. Am. Chem. Soc. 1996, 118, 11970-11971.

4936 J. Am. Chem. Soc., Vol. 120, No. 20, 1998
Uchiyama et al.
Table 2. Intermolecular Epoxide Opening Reaction
Table 3. Bromine-Zinc Exchange (1)
Figure 3. 1H NMR spectra of organozincates in THF (-20 °C).
structures of the tetraalkylzincates are in a tetrahedral (sp3 like)
dianionic arrangement, while those of the trialkylzincates are
in a trigonal (sp2 like) monoanionic arrangement about the Zn
atom.9
(7), was estimated. The results are listed in Table 2. The
reaction with Me3ZnLi gave almost equal amounts of 6 and 7.
Me4ZnLi2 also showed similar selectivity, although the yield
(6 + 7) was increased. Furthermore, the reaction with Me3-
Zn(CN)Li2 and Me3Zn(SCN)Li2 gave 7 as a major product,
while the reaction with MeLi and Me2Cu(CN)Li2 gave 6 as a
major product. Although the reasons for the divergent selectiv-
ity are not clear at present, the inverse selectivity between Me3-
Zn(CN)Li2 and Me2Cu(CN)Li2 is attractive from a synthetic
viewpoint.
The addition of 1 equiv of Me3SiCN or Me3SiNCS to the
Me4ZnLi2 solution should give the zincates with a methyl group
replacement by the CN or SCN ligand. As we expected, the
reaction of the tetramethylzincate with Me3SiCN and Me3SiNCS
gave the new zincates, Me3Zn(CN)Li2 (3) and Me3Zn(SCN)-
Li2 (4a), and their methyl signals were observed as sharp singlets
(-1.20 ppm for 3 and -1.23 ppm for 4a). Also, the signal of
the newly generated tetramethylsilane in the mixture was
observed at 0.00 ppm together with the disappearance of the
signal of Me3SiCN (0.38 ppm) or Me3SiNCS (0.40 ppm). As
an alternative way to prepare CN or SCN ligated zincates, the
reaction of Zn(CN)2 or Zn(SCN)2 with 3 equiv of MeLi was
Bromine-Zinc Exchange Reaction of Bromobenzene
Derivatives Using Newly Designed Zincates. We have
reported that Me3ZnLi is effective for the selective iodine-
zinc exchange reaction of functionalized aromatic iodides;
however, aromatic bromides were unreactive to this metalation
process.3a Since newly designed zincates are considered to have
more anionic character on the basis of our preliminary 1H NMR
study, the bromine-zinc exchange reaction of bromobenzene
(8) was then investigated (Table 3). First, in order to investigate
the difference in the reactivity toward the bromine-zinc
exchange reaction of bromobenzene between newly designed
zincates and Me3ZnLi (normally coordinated zincates), the
reaction was carried out at fixed conditions (-20 °C, 2 h) and
the resulting metal species was trapped with benzaldehyde. The
reaction using Me4ZnLi2 proceeded to give benzhydrol (9) in
47% yield (entry 3). Under the same reaction conditions, the
reaction with Me3ZnLi did not proceed at all and MeLi was
also found inactive under the same conditions (entries 1 and
2). The modified zincates, Me3Zn(CN)Li2 and Me3Zn(SCN)-
Li2, showed moderate reactivity toward the bromine-zinc
exchange reaction and 9 was obtained in 22% and 23% yields,
respectively (entries 4 and 5).
1
examined. From the preliminary H NMR study, the reaction
of Zn(CN)2 with MeLi is sluggish and no formation of a zincate
was observed,10 while the reaction of Zn(SCN)2 with MeLi gave
a zincate (-1.31 ppm) similar to 4a. These results indicate
that the different zincate species are formed except for the
reaction of Zn(CN)2 with MeLi, and we are intrigued by the
enhanced anionic character of these newly designed zincates
compared to Me3ZnLi to investigate the following reactions.
Intermolecular Ring Opening Reaction of Epoxides Using
Various Zincates. The regioselectivity of intermolecular ring
opening reaction of epoxides was investigated by focusing on
the nature of the organometallic reagent, such as the Lewis
acidity or basicity.11 Styrene oxide was reacted with various
organometallic derivatives, and the ratio of the two isomeric
compounds, 1-phenyl-1-propanol (6) and 2-phenyl-1-propanol
(9) For recent review, see: Weiss, E. Angew. Chem., Int. Ed. Engl. 1993,
32, 1501-1523.
(10) For recent discussion on the structure of Zn(CN)2, see: Hoskis, B.
F.; Robson, R. J. Am. Chem. Soc. 1990, 112, 1546-1554.
(11) Smith, J. G. Synthesis 1984, 629-656.

New Formulas for Organozincate Chemistry
J. Am. Chem. Soc., Vol. 120, No. 20, 1998 4937
Table 5. Bromine-Zinc Exchange (3)
Table 4. Bromine-Zinc Exchange (2)
Next, we optimized the reaction conditions toward the
bromine-zinc exchange reaction of bromobenzene using newly
designed zincates, and applied for the reaction of a function-
alized aromatic bromide (Table 4). Although the favorable
reaction temperature depends to some degree on the newly
designed zincates, the bromine-zinc exchange reaction pro-
ceeded smoothly to give benzhydrol (11; R ) H) in excellent
yields for all the bromobenzenes (entries 1-3). In connection
with our recent studies on the chemoselective metalation reaction
of functionalized aromatic compounds,3 we then investigated
the bromine-zinc exchange reaction of 4-substituted bromoben-
zenes. Newly designed zincates were also proved to be effective
for the metalation reaction of 4-methoxybromobenzene (entries
4-6). However, during the reaction of methyl 4-bromoben-
zoate, complex mixtures were obtained in all cases, because
the rate of the bromine-zinc exchange reaction was considered
to be almost equal to that of the methylation reaction toward a
methyl ester.
We then investigated the bromine-zinc exchange reaction
of 4-cyanobromobenzene (12) using newly designed zincates
(Table 5). In the reaction using Me3Zn(CN)Li2 and Me3Zn-
(SCN)Li2, 4-cyanobenzhydrol (13), the expected product, was
obtained as the sole product in high yields (entries 1 and 2).
However, when Me4ZnLi2 was used as a metalating reagent,
the reaction proceeded further to give 4-acetylbenzhydrol (14)
in 63% yield (entry 3). A possible mechanism for this
unexpected reaction is shown in Figure 4. To begin with, the
bromine-zinc exchange reaction of 14 with Me4ZnLi2 pro-
ceeded to give 16 and the subsequent reaction with benzaldehyde
gave the expected lithium alkoxide (17). However, the cyano
group of 17 more reacted with residual Me3ZnLi to give 18.
Furthermore, 14 was considered to be obtained by hydrolysis
(workup).
Table 6. Tellurium-Zinc Exchange Reaction
zinc exchange reaction) to give 4-acetylbromobenzene (15)
(Table 5, entry 4). The result strongly supports the proposed
reaction mechanism. Also, these results of the halogen-zinc
exchange reaction with various zincates indicate that the
reactivities of zincates reflect the value of the high field shift
of δMe of the reagents.
Tellurium-Zinc Exchange Reaction of 2-Pyridinyltellu-
rium Compounds. Synthetic applications of organotellurium
compounds have increased in recent years.12 Among their many
synthetic uses, transmetalation reaction with organolithium or
organocuprate reagents are considered to be important for
carbon-carbon bond formation.13 In connection with our recent
studies on pyridinylmetal derivatives,14 we investigated the
tellurium-zinc exchange reaction of 2-pyridinyltellurium com-
pounds using various zincates (Table 6). Butyl 2-pyridyltellu-
ride (19) was prepared by the nucleophilic substitution of
2-bromopyridine and 2-chloropyridine with lithium butanetel-
luroate to give the telluride (19) in 70% and 61% yields,
respectively.13c Compound 19 was treated with Me4ZnLi2 in
THF at 0 °C in 2 h and then with benzaldehyde to give phenyl-
(2-pyridinyl)methanol (20) in 81% yield (entry 2), while the
reaction with Me3ZnLi did not proceed at all even under a
Indeed, the reaction of 12 using Me3ZnLi as a metalating
reagent proceeded only methylation reaction (not the bromine-
(12) For recent review, see: Petragnani, N. Tellurium in Organic
Synthesis; Academic Press: London, 1994.
(13) (a) Hiiro, T.; Morita, Y.; Inoue, T.; Kambe, N.; Ogawa, A.; Ryu,
I.; Sonoda, N. J. Am. Chem. Soc. 1990, 112, 455-456. (b) Tucci, F. C.;
Chieffi, A.; Comasseto, J. Tetrahedron Lett. 1992, 33, 5721-5724. (c)
Kondo, Y.; Shilai, M.; Uchiyama, M.; Sakamoto, T. J. Chem. Soc., Perkin
Trans. 1 1996, 1781-1782.
(14) (a) Sakamoto, T.; Kondo, Y.; Murata, N.; Yamanaka, H. Tetrahedron
Lett. 1992, 33, 5373-5374. (b) Sakamoto, T.; Kondo, Y.; Murata, N.;
Yamanaka, H. Tetrahedron 1993, 49, 9713-9720.
Figure 4. Possible mechanism for the formation of 14.

4938 J. Am. Chem. Soc., Vol. 120, No. 20, 1998
Table 7. Intramolecular Michael Addition
Uchiyama et al.
survey whether the zincates could be used for intramolecular
carbometalation reaction toward the alkene possessing no
activation group (COOR, CN, etc.).16 First, intramolecular
carbozincation reaction was examined using the iodine-zinc
exchange reaction of the allyl 2-iodophenyl ether (23). When
23 was treated with Me3ZnLi, the halogen-metal exchange
reaction proceeded smoothly but no intramolecular carbometa-
lation reaction was observed (Scheme 2, top). On the other
hand, the reaction of 23 with Me4ZnLi2 followed by hydrolysis
gave 3-methyl-2,3-dihydrobenzo[b]furan (28) in 42% yield,
which probably results from the intramolecular carbozincation
reaction of arylzincate (26) (Scheme 2, bottom). However,
during the reaction of 23 with Me3Zn(CN)Li2, Me3Zn(SCN)-
Li2, and Me2Cu(CN)Li2, the intramolecular carbozincation
reaction did not proceed at all. This method was also applicable
to a synthesis of substituted indoline derivatives (Scheme 3).
Intramolecular Epoxide Opening Reaction. Our next
interest was focused on the intramolecular ring opening reaction
of epoxide 33 using the zincates as metalating agents (Table
8).17 Interestingly, all newly designed zincates showed almost
the completely opposite regioselectivity from Me3ZnLi for the
ring opening reaction. Especially, the reaction with Me3ZnLi
and the reaction with Me3Zn(SCN)Li2 showed almost perfect
reverse regioselectivity (entries 1 and 4). The reaction with
Me3ZnLi gave an anti-Baldwin’s rule product,18 endo-cyclized
1,2,3,4-tetrahydroquinoline derivative (35), as the major product,
while the reaction with Me3Zn(SCN)Li2 gave the exo-cyclized
indoline derivative (34). This method was considered to be
applicable for the chiral synthesis of 3-indolinemethanol deriva-
tives and 3-hydroxytetrahydroquinoline derivatives, key precur-
sors for the synthesis of CC-1065/duocarmycin pharmacophore
known as potent antitumor antibiotics (Figure 5).19-21
harsher conditions (room temperature, 18 h) (entry 1). The
modified zincates, Me3Zn(CN)Li2 and Me3Zn(SCN)Li2, also
showed high reactivity toward the tellurium-zinc exchange
reaction although it required the higher temperature and 20 was
obtained in 63% and 58% yields, respectively (entries 4 and
5). From these results, the tellurium-zinc exchange reaction
using newly designed zincates is considered to proceed smoothly
to form the newly designed 2-pyridinyl zincates.
All these results make it clear that the newly designed zincates
have higher reactivity toward the halogen (or tellurium)-zinc
exchange reaction than the “normally tricoordinated” zincate,
Me3ZnLi. These results also support the structural difference
between the newly designed zincates and Me3ZnLi.
Intramolecular Michael Addition Reaction. Our next
interest was focused on the reactivities of arylzinc ate complexes,
generated in situ from the halogen-zinc exchange reaction of
zincates, toward various electrophiles. Intramolecular Michael
addition was then examined using the iodine-zinc exchange
reaction of 21 (Table 7). The reaction of 21 (X ) O, NSO2Ph)
with ordinary Me3ZnLi did not proceed at all, although the
iodine-zinc exchange reaction occurred (entries 1 and 2).15
However, when Me3Zn(CN)Li2 and Me3Zn(SCN)Li2 in place
of Me3ZnLi were used, the reaction proceeded to give the
expected product (22) in moderate yields (entries 3-6).
Furthermore, Me4ZnLi2 showed high reactivity toward the
intramolecular Michael addition reaction, and 22 was obtained
(entries 7 and 8). These results indicate that trialkylmonoaryl-
zincates, generated from aryl iodide and newly designed
zincates, are a more reactive species toward R,â-unsaturated
compounds than the ordinary (“normally tricoordinated”) aryldi-
methylzincates. These results indicate that newly designed
zincates are useful reagents not only for the Michael addition
reaction, but also for the selective iodine-zinc exchange reaction
of iodobenzene derivatives possessing an ester moiety. Namely,
the rate of the iodine-zinc exchange reaction using newly
designed zincates (in contrast to the bromine-zinc exchange
reaction) proved to be faster than that of the methylation of the
ester.
Interestingly, the cyano-modified reagents, Me3Zn(CN)Li2
and Me2Cu(CN)Li2, showed the completely opposite regiose-
lectivity in this system. R2Cu(CN)Li2 has been called a “higher
order cuprate” 22 implying dianionic Cu(I) species containing
three covalently bonded ligands on Cu and the structure of these
cuprates has been a controversial issue.23 However recent
studies on the structure revealed that the CN ligand is not on
(16) For recent examples, see: (a) Zhang, D.; Liebeskind, L. S. J. Org.
Chem. 1996, 61, 2594-2595. (b) Bailey, W. F.; Jiang, X.-L. J. Org. Chem.
1996, 61, 2596-2597. (c) Nakao, J.; Inoue, R.; Shinokubo, H.; Oshima,
K. J. Org. Chem. 1997, 62, 1910-1911.
(17) For recent discussion on the regioselectivity in cyclization, see: (a)
Parham, W. E.; Bradsher, C. K. Acc. Chem. Res. 1982, 15, 300-305. (b)
Brasher, C. K.; Reames, D. C. J. Org. Chem. 1978, 43, 3800-3802. (c)
Last, L. A.; Fretz, E. R.; Coates, R. M. J. Org. Chem. 1982, 47, 3211-
3219. (d) Cook, M. P., Jr.; Houpis, I. N. Tetrahedron Lett. 1985, 26, 3643-
3646. (e) Babler, J. H.; Bauta, W. E. Tetrahedron Lett. 1984, 25, 4323-
4324. (f) Hardcastle, I. R.; Quale, P.; Ward, E. L. M. Tetrahedron Lett.
1994, 35, 1747-1748. (g) Dhawan, K. L.; Gowland, B. D.; Durst, T. J.
Org. Chem. 1980, 45, 924-926. (h) Rieke, R. D.; Stack, D. E.; Dawson,
B. T.; Wu, T.-C. J. Org. Chem. 1993, 58, 2483-2491.
(18) (a) Baldwin, J. E. J. Chem. Soc., Chem. Commun. 1976, 734-736.
(b) Johnson, C. D. Acc. Chem. Res. 1993, 26, 476-482.
(19) (a) Chidester, C. G.; Krueger, W. C.; Mizsak, S. A.; Duchamp, D.
J.; Martin, D. G. J. Am. Chem. Soc. 1981, 103, 7629. (b) Takahashi, I.;
Takahashi, K.; Ichimura, M.; Morimoto, M.; Asano, K.; Kawamoto, I.;
Tomita, F.; Nakano, H. J. Antibiot. 1988, 41, 1915. (c) Ichimura, M.; Ogawa,
T.; Takahashi, K.; Kobayashi, E.; Kawamoto, I.; Yasuzawa, T.; Takahashi,
I.; Nakano, H. J. Antibiot. 1990, 43, 1037.
(20) CC-1065 synthesis: (a) Boger, D. L.; Coleman, R. S. J. Am. Chem.
Soc. 1988, 110, 1321-1323. (b) Boger, D. L.; Coleman, R. S. J. Am. Chem.
Soc. 1988, 110, 4796-4807. (c) Kelly, R. C.; Gebhard, I.; Wicnienski, N.;
Aristoff, P. A.; Johnson, P. D.; Martin, D. G. J. Am. Chem. Soc. 1987,
109, 6837-6838.
(21) Duocarmycin synthesis: (a) Boger, D. L.; Machiya, K. J. Am. Chem.
Soc. 1992, 114, 10056-10058. (b) Boger, D. L.; Machiya, K.; Hertog, D.
L.; Kitos, P. A.; Holmes, D. J. Am. Chem. Soc. 1993, 115, 9025-9036. (c)
Muratake, H.; Abe, I.; Natsume, M. Tetrahedron Lett. 1994, 35, 2573-
2576.
Intramolecular Carbozincation Reaction. These high
reactivities of newly designed arylzincates prompted us to further
(15) Review: (a) Perlmutter, P. Conjugate Addition Reactions in Organic
Synthesis; Pergamon Press: Oxford, 1992. (b) ComprehensiVe Organic
Synthesis, Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991;
Vol. 4.

New Formulas for Organozincate Chemistry
J. Am. Chem. Soc., Vol. 120, No. 20, 1998 4939
Scheme 2. Intramolecular Carbozincation (1)
Scheme 3. Intramolecular Carbozincation (2)
ture) into account,8,9 we cannot omit the possibility of the
ligation of CN or SCN to the Zn atom. In addition, because
studies to compare the reactivity of these reagents disclosed a
different regioselectivity for intermolecular epoxide opening
reaction and a different reactivity toward the halogen (or
tellurium)-zinc exchange reaction, Michael addition reaction,
and carbozincation reaction, these “newly designed” zincates
should be distinguished from ordinary lithium trialkylzincates
in structure and reactiVity.
Table 8. Intramolecular Epoxide Opening Reaction
1H NMR/Raman/React-IR(In Situ FTIR)/EXAFS Study
of Newly Designed Zincates. From the preliminary 1H NMR
study, the methyl signals of Me2Zn, Me4ZnLi2 (2), Me3ZnLi
(1), and MeLi in THF at -20 °C were observed as sharp singlets
at -0.84, -1.44, -1.08, and -1.96 ppm, respectively (Figure
3, Tables 1 and 9). The high field shift of 2 from the value of
1 is considered to indicate the more anionic character of the
newly designed zincates. Indeed, the crystal structure of 2 is
known to be a tetracoordinated, dianionic zinc structure.8,9
Furthermore, the methyl signals of the cyano- and thiocyano-
substituted newly designed zincates, Me3Zn(CN)Li2 (3) and Me3-
Zn(SCN)Li2 (4a) were observed as sharp singlets (-1.20 ppm
for 3 and -1.23 ppm for 4a) together with the signal of the
newly generated Me4Si. The methyl signals of the free Me3-
ZnLi (1) and MeLi were not observed in a THF solution of
Me3Zn(CN)Li2 (3) or Me3Zn(SCN)Li2 (4a); however, we do
not have enough evidence to neglect the possibility of a fast
exchange on the NMR time scale.
the Cu atom but on the Li atom.23,24 The structure of the newly
designed zincates with the CN or SCN ligand has never been
studied. Taking the tendency of zinc derivatives to form
complexes with tetrahedral configuration (sp3 hybridized struc-
Secondly, we measured the Raman spectra of Me3Zn(SCN)-
Li2 (4a) and LiSCN (Figure 6). In the spectrum of LiSCN (top
(23) (a) Snyder, J. P.; Spangler, D. P.; Behling, J. R.; Rossiter, B. E. J.
Org. Chem. 1994, 59, 2665-2667. (b) Barnhart, T. M.; Huang, H.; Penner-
Hahn, J. E. J. Org. Chem. 1995, 60, 4310-4311. (c) Snyder, J. P.; Bertz,
S. H. J. Org. Chem. 1995, 60, 4312-4313. (d) Bertz, S. H.; Miao, G.;
Eriksson, M. Chem. Commun. 1996, 815-816.
(24) Stemmler, T. L.; Barnhart, T. M.; Penner-Hahn, J. E.; Tucker, C.
E.; Knochel, P.; Boehme, M.; Frenking, G. J. Am. Chem. Soc. 1995, 117,
12489-12497.
(22) (a) Lipshutz, B. H.; Wilhelm, R. S.; Floyd, D. M. J. Am. Chem.
Soc. 1981, 103, 7672-7674. (b) Lipshutz, B. H.; Wilhelm, R. S.; Kozlowski,
J. A. Tetrahedron 1984, 40, 5005-5038. (c) Lipshutz, B. H.; Kozlowski,
J. A.; Wilhelm, R. S. J. Org. Chem. 1984, 49, 3943-3949. (d) Lipshutz,
B. H. Synthesis 1987, 325-341. (e) Lipshutz, B. H.; Sharma, S; Ellsworth,
E. L. J. Am. Chem. Soc. 1990, 112, 4032-4034. (f) π-Bound structure,
see: Lipshutz, B. H.; James, B. J. Org. Chem. 1994, 59, 7585-7587.

4940 J. Am. Chem. Soc., Vol. 120, No. 20, 1998
Uchiyama et al.
Figure 5.
Table 9. 1H NMR of Zincates in THF (-20 °C)
In situ Fourier transform infrared (FTIR) spectroscopy has
become an important technology for the investigation of
chemical reactions in recent years.6b,25 We then monitored the
formation of Me3Zn(SCN)Li2 (4a) by the In Situ FTIR 1000
system (in situ FTIR) equipped with an immersible DiComp
Attenuated Total Reflectance (ATR) probe in order to track the
reaction of Me3SiNCS with Me4ZnLi2 (2) in a THF solution
(Figure 7). Infrared bands at 837, 855, and 1254 cm-1 in the
spectrum of the starting material (Me3SiNCS) were assigned
to the methyl stretching vibration of the trimethylsilyl moiety,
and diminished in intensity as the reaction proceeded. Further-
more, the bands at 863 and 1246 cm-1, assigned to the methyl
stretching vibration of the newly generated tetramethylsilane,
increased in intensity. On the other hand, the reaction profile
also shows the formation of a new zincate species as indicated
by the decrease in intensity of the 2084 cm-1 isothiocyano band
of the starting material (Me3SiNCS) and the increase in intensity
of the new (iso)thiocyano band at 2070 cm-1. These present
entry
metal reagent
δ
Me (ppm)a
1
2
3
4
5
6
Me2Zn
Me3ZnLi
Me4ZnLi2
Me3Zn(SCN)Li2
Me3Zn(CN)Li2
Zn(SCN)2 + 3MeLi
-0.84
-1.08
-1.44
-1.23b
-1.20b
-1.31
a The δ values are relative to â methylene proton (1.85 ppm) to
THF. b The signal of tetramethylsilane newly generated in the mixture
was observed at 0.00 ppm together with disappearance of the signal of
Me3SiNCS (0.40 ppm) or Me3SiCN (0.38 ppm).
1
results, i.e., the H NMR/Raman/in situ FTIR studies of the
newly designed zincate solution, strongly support the existence
of the new zincates. Although the implication from of the results
the Raman/in situ FTIR spectroscopic experiments is that the
(iso)thiocyano ligand must be incorporated somehow within the
zincate cluster, there is no guarantee that the Zn-SCN covalent
bonding exists.
In order to obtain direct information about the structures of
the newly designed zincates, we measured the EXAFS spectra
of the organozinc reagents and other organometallic reagents.26
Extended X-ray absorption fine structure (EXAFS) spectroscopy
probes the local structures, i.e., the nature, number, and distance
of near neighbors which surround atoms or ions of a chosen
element within noncrystalline systems.27 The laboratory X-ray
spectrometer employed for the XAFS measurements has been
previously described28 as well as the details of the analysis
procedure.
Figure 6. Raman spectra (514.5 nm excitation) of THF solutions of
LiSCN (top) and Me3Zn(SCN)Li2 (bottom).
The Fourier transform of the EXAFS data for THF solutions
(∼0.2 M) of Me2Zn, Me4ZnLi2 (2), and Me4ZnLi2 + Me3SiCN
(3), and Zn(CN)2 in the solid phase are shown in Figure 8. The
spectra give a pseudoradial distribution function around the
trace), a single strong band, which is assignable to the C-S
stretching vibration of SCN on the Li atom or free SCN anion,
appears at 779 cm-1. On the other hand, Me3Zn(SCN)Li2 (4a)
shows no band at 779 cm-1 (bottom trace). Namely, free LiSCN
(or SCN- ion) does not exist in a THF solution of Me3Zn(SCN)-
Li2 (4a).
(26) A part of the work was communicated in: Uchiyama, M.; Kondo,
Y.; Miura, T.; Sakamoto, T. J. Am. Chem. Soc. 1997, 119, 12372-12373.
(27) See, for example: X-ray Absorption: Principles, Applications, and
Techniques of EXAFS, SEXAFS and XANES; Prins, R., Koningsberger, D.,
Eds.; Wiley: New York, 1988.
(28) Mizushima, T.; Tohji, K.; Udagawa, Y.; Ueno, A. J. Am. Chem.
Soc. 1990, 112, 7887-7893.
(25) (a) Lynch, J. E.; Riseman, S. M.; Laswell, W. L.; Tschaen, D. M.;
Volante, R. P.; Smith, G. B.; Shinkai, I. J. Org. Chem. 1989, 54, 3792. (b)
Paul, P. P.; Kirlin, K. D. J. Am. Chem. Soc. 1991, 113, 6331.

New Formulas for Organozincate Chemistry
J. Am. Chem. Soc., Vol. 120, No. 20, 1998 4941
Figure 7. FTIR spectroscopic analysis of the reaction of Me3SiNCS (1.0 M) with Me4ZnLi2 (1.0 M) in THF at -78 °C.

4942 J. Am. Chem. Soc., Vol. 120, No. 20, 1998
Uchiyama et al.
EXAFS, since the crystal structure of Zn(CN)2 is known.29 Also,
the existence of this peak supports the fact that Zn(CN)2 (s) is
an oligomeric structure as previously reported.29
The EXAFS study of the Me3Zn(CN)Li2 (3) solution led us
to the conclusion that the cyanide and all of the methyl groups
are coordinated to the Zn atom in Me3Zn(CN)Li2, that is, the
existence of a four coordinated dianionic zincate is confirmed.
Theoretical (DFT) Study of Newly Designed Zincates and
Comparison with Experimental/Spectroscopic Data. The use
of ab initio methods to obtain accurate data on the structures
and properties of molecules has become a routine technique in
the chemistry of heavy-atom molecules, as well as light-atom
molecules.
In order to evaluate the four-coordinated dianionic structure
of the newly designed zincates, we first carried out theoreticalcal
culations based on the density-functional theory (DFT)30 using
the computer program MULLIKEN,31 where a slightly modified
version of the B3LYP function is implemented; in Mulliken
the local correlation functional of Vosko, Wilk, and Nusair32 is
replaced by the functional of Perdew and Wang.33 Hybrid
density functional methods have been shown to give as good
or better geometries as correlated ab initio methods for first-
row transition-metal complexes.34 The basis set for zinc was
the double-ú basis (62111111/3111/311) of Scha¨fer et al.,35
enhanced with diffuse p, d, and f functions with exponents 0.174,
0.132, and 0.390, and 6-31G* for the other atoms.36 The
calculated Zn-C bond lengths of ZnMe2 at B3LYP (1.955 Å)
are in reasonable agreement with the X-ray distance of 1.928
Å.37
Figure 8. Fourier transform of the EXAFS spectra.
With this background, we studied theoretically the structures
and the relative energies of the tetraorganozincates. Although
the relative energies of the zincates depend to some degree on
the substitutent (R), the tri-coordinated monoanionic zincates,
36b and 37c, are energetically favored over the tetracoordinated
dianionic zincates, 36a and 37a, in both cases (Me3Zn(R)Li2;
R ) Me and CN) (Figure 10). Also, the tetracoordinated
dianionic Me3Zn(SCN)Li2 (38a) calculations were carried out
using the following model; a Zn atom is surrounded by four
tetrahedrally coordinated carbon atoms, one of which is SCN
and the others are methyls (Figure 11). Optimization with
B3LYP causes a no-barrier rearrangement of the tetrahedral
(dianionic) arrangement to the tricoordinated SCN-bridged
structure (38b). In conclusion, the present DFT study predicted
that monomeric lithium tetraorganozincates (symbolized as Me3-
Figure 9. FEFF6 calculation of Me3Zn(CN)Li2.
absorbing atom (Zn). Peak positions in the Fourier transform
are shifted by about 0.5 Å due to a phase shift. Only one and
a similar principal feature is observed for both Me2Zn and 2.
These peaks are attributed to the Zn-C nearest neighbors.
On the other hand, the Fourier transform for 3, which was
prepared by the reaction of Me4ZnLi2 (2) with Me3SiCN in a
THF solution, i.e., Me3Zn(CN)Li2 (3), shows a second feature
in addition to the nearest neighbor peak. A new peak is
considered to be attributed to Zn-C-N next nearest neighbors.
To be more precise, the presence of the feature indicates that
the CN ligand is on the Zn atom in Me3Zn(CN)Li2. FEFF6
calculations have been carried out using the following model;
a Zn atom is surrounded by four tetrahedrally coordinated carbon
atoms, one of which is CN and the others are methyl. The
observed spectrum was almost reproduced when Zn-C nearest
neighbors and Zn-C-N next nearest neighbors distances were
set to 1.96 and 3.10 Å, respectively (Figure 9). CN distance is
calculated to be 1.14 Å which is very close to the one observed
in Zn(CN)2.29 Indeed, the Fourier transform for Zn(CN)2 (s)
of which cyanide is coordinated to the Zn atom, have similar
peaks.
(30) (a) Becke, A. D. Phys. ReV. 1988, A38, 3098. (b) Becke, A. D. J.
Chem. Phys. 1993, 98, 1372. (c) Becke, A. D. J. Chem. Phys. 1993, 98,
5648. (d) Lee, C.; Yang, W.; Parr, R. G. Phys. ReV. 1988, B37, 785.
(31) Mulliken (version 2.0): A Computational Quantum Chemistry
Program developed by Rice, J. E.; Horn, H.; Lengsfield, B. H.; McLean,
A. D.;Carter, J. T.; Replogle, E. S.; Barnes, L. A.; Maluendes, S. A.; Lie,
G. C.; Gutowski, M.; Rudge, W. E.; Stephan, P. A.; Sauer, P. A.; Lindh,
R.; Andersson, K.; Chevalier, T. S.; Widmark, P. -O.; Bouzida Djamal;
Pascansky, G.; Singh, K.; Gillan, C. J.; Carnevali, P.; Swope, W. C.; Liu,
B. Almaden Reserch Center, IBM ReserchDivision, 650 Harry Road, San
Jose, CA 95120-6099.
(32) Vosko, S. H.; Wilk, L.; Nusair, M. Can. J. Phys. 1980, 58, 1200.
(33) Perdew, J. P.; Wang, Y. Phys. ReV. 1992, B45, 13244.
(34) (a) Ricca, A; Bauschlicher, C. W. J. Chem. Phys. 1994, 98, 12899-
12903. (b) Ricca, A; Bauschlicher, C. W. Theor. Chim. Acta. 1995, 92,
123-131. (c) Holthausen, M. C.; Mohr, M; Koch, W. Chem. Phys. Lett.
1993, 98, 5648.
(35) Scha¨fer, A; Horn, H.; Ahlrichs, R. J. Chem. Phys. 1992, 97, 2571-
2577.
(36) Hehre, W. J.; Radom, L.; Schleyer, P. v. R.; Pople, J. A. Ab initio
molecular orbital theory; Wiley-Interscience: New York, 1986.
(37) McKean, D. C.; McQuillan, G. P.: Thompson, D. W. Spectrochim.
Acta 1980, 36A, 1009.
Moreover, a second outer-shell peak is also observed for Zn-
(CN)2 (s). This peak can be assigned Zn‚‚‚Zn (Zn-C-N-Zn)
(29) For recent discussion on the structure of Zn(CN)2, see: Hoskins,
B. F.; Robson, R. J. Am. Chem. Soc. 1990, 112, 1546-1554.

New Formulas for Organozincate Chemistry
J. Am. Chem. Soc., Vol. 120, No. 20, 1998 4943
Figure 10. Relative energies for B3LYP-optimized isomers of Me3Zn(R)Li2 (R ) Me, CN).
Scheme 4. Possible Equilibrium between Tetracoordinated
Zincates And R-Bridged Tricoordinated Zincates
Figure 11.
structure. Secondly, we considered the existence of an equi-
librium between the tetracoordinated zincates (39) and the
R-bridged tricoordinated zincates (40) as a reasonable explana-
tion of these antipodal results. Since this equilibrium is
sufficiently fast compare to the EXAFS or X-ray time scale, a
tetracoordinated structure was considered to be observed in
opposition to the real thermodynamic stability. Also, on the
basis of the experimental data (the excellent chemical yields
and chemoselectivity), newly designed zincates were expected
to be differentiated from ordinary triorganozincates, R3ZnLi.
The thermodynamically most stable species is not always the
real active species. Small amounts of tetracoordinated dianionic
zincate in the reaction mixture may be active species and this
equilibrium may be shifted to the left as the reaction proceeds
(Scheme 4).
Zn(R)Li2; R ) Me, CN, and SCN) prefer a Zn(II) tricoordinate
R-bridged structure rather than a tetracoordinated dianionic
structure.
1
All the results, including the H NMR/Raman/in situ FTIR/
EXAFS spectroscopies and DFT theoretical studies of the newly
designed zincates, strongly support the fact that Me3Zn(R)Li2
(R ) Me, CN, SCN) are new category of zincate species.
Especially, EXAFS spectroscopy of the cyano-substituted zin-
cate (Me3Zn(CN)Li2) supported the tetracoordinate, dianionic
zinc structures and the CN ligand is directly coordinated to the
Zn atom in these zincates. Also, X-ray studies of the zincates
have disclosed that the crystal structure of the tetraalkylzincates
and trialkylzincates are in a tetrahedral (sp3 like) dianionic
arrangement and a trigonal (sp2 like) monoanionic arrangement
about the Zn atom, respectively.7,8 These observations are also
identical with the experimental facts that newly designed
zincates have higher reactivities (halogen (or tellurium)-zinc
exchange, Michael addition, and carbozincation) and different
chemoselectivities (epoxide ring opening reaction) compared
to the triorganozincates. However, theoretical studies suggested
an opposite result, that is, Me3Zn(R)Li2 is not a tetracoordinated
zincate, dianionic Zn(II) salt, but a modified triorganozincate.
Why were two totally distinct results obtained? How do we
understand these antipodal results? First, we do not have enough
evidence to neglect the possibility of the existence of a dimer
or polymer, while we carried out DFT calculations of model
compounds due to computational simplicity on the supposition
that these zincates exist as monomers. The tetracoordinated
dianionic structure might be most stable in the zincate polymeric
Presently, we can neither confirm the tricoordinated R-bridged
structure nor omit the possibility of the tetracoordinated
structure. However, it is evident that newly designed zincates
are new species and effective reagents not only for the reaction
of various kinds of electrophiles but also for the metalation of
aromatic halides or tellurides.
Conclusion
We have shown the unique reactivities of various newly
designed ate complexes of organozinc derivatives, Me3Zn(R)-
Li2 (R ) Me, CN, SCN), arising from lithium trimethylzincate
and anion species such as methyllithium, lithium cyanide, and
lithium thiocyanate; these zincates proved to be effective for
the chemoselective halogen (or tellurium)-zinc exchange,

4944 J. Am. Chem. Soc., Vol. 120, No. 20, 1998
Uchiyama et al.
1
The ratio of the two products were determined by analyzing the H
Michael addition, carbozincation, and epoxide ring opening
reactions. We have also measured the 1H NMR/Raman/in situ
FTIR/extended X-ray absorption fine structure (EXAFS) spectra
of the organozinc reagents and organometallic reagents, and
carried out the density-functional theory (DFT) theoretical
calculations of the newly designed zincates to obtain information
about the structures of these newly designed zincates. Although
it is very hard to come to a complete conclusion, we proposed
some hypotheses. We believe the present idea would provide
a new way for designing useful organozinc and organometallic
reagents for organic synthesis.
NMR spectrum of the mixture comparing with the authentic samples.
1-Phenyl-1-propanol (6): 300 MHz H NMR (CDCl3/TMS) δ (ppm)
0.90 (3H, t, J ) 7.6 Hz), 1.71-1.86 (1H, m), 1.97 (1H, bs), 4.57 (1H,
t, J ) 6.6 Hz), 7.24-7.36 (5H, m). 2-Phenyl-1-propanol (7): 300 MHz
1H NMR (CDCl3/TMS) δ (ppm) 1.26 (3H, d, J ) 7.1 Hz), 1.54 (1H,
brs), 2.94 (1H, sextet, J ) 7.1 Hz), 3.68 (2H, d, J ) 6.9 Hz), 7.20-
7.36 (5H, m).
General Procedure for Bromine-Zinc Exchange Reaction.
Under Ar atmosphere, a THF solution of a zincate (1.1 mmol) were
prepared as described above. The THF solution of the zincate (1.1
mmol) was cooled to 0 °C and bromobenzene (8) (165.3 mg, 1.0 mmol)
in THF (3 mL) was added dropwise to the mixture. After the mixture
was stirred for 2 h, benzaldehyde (0.21 mL, 2.0 mmol) was added and
stirring was continued for 3 h at room temperature. The solvent was
removed under reduced pressure, and the residue was treated with NH4-
Cl (30 mL) followed by extraction with CH2Cl2 (30 mL × 3). The
CH2Cl2 layer was dried over MgSO4, and the CH2Cl2 was removed
under reduced pressure. The residue was purified by SiO2 column
chromatography using AcOEt-hexane (1:5) as an eluent to give
benzhydrol (9): mp 65-67 °C (recrystallized from n-hexane/ethyl
acetate, colorless plates) (lit.39 mp 68 °C); 300 MHz 1H NMR (CDCl3/
TMS) δ (ppm) 2.21 (1H, d, J ) 3.3 Hz), 5.85 (1H, brs), 7.2-7.5 (10H,
m); MS m/z 184 (M+).
1
Experimental Section
General Methods. Melting points were determined with a Yazawa
micro melting point apparatus and uncorrected. 1H NMR spectra were
recorded on a Varian Gemini 2000 using tetramethylsilane as an internal
standard. 1H NMR spectra of zincates and other organometallic
compounds were recorded on a JEOL GX-500. Chemical shifts are
expressed in δ (ppm) values, and coupling constants are expressed in
hertz (Hz). The following abbreviations are used: s ) singlet, d )
doublet, m ) multiplet, and brs ) broad singlet. Low-resolution mass
spectra (MS) and high-resolution mass spectra (HRMS) were recorded
on a JOEL JMS-O1SG-2 spectrometer. Tellurium (-40 mesh,
99.997%) was obtained from Aldrich Chemical Co. MeLi in Et2O was
obtained from Kanto Chemical, Co. Ltd. The concentration of MeLi
was determined by titration prior to use.38
Preparation of Organozinc Derivatives. Preparation of Me3ZnLi.
Under Ar atmosphere, MeLi (1.02 M Et2O solution, 1.10 mL, 1.125
mmol) was added to a mixture of dry THF (3 mL) and ZnCl2 (1 M
THF solution, 0.375 mL, 0.375 mmol) at 0 °C, and the mixture was
stirred for 30 min at the temperature.
Preparation of Me4ZnLi2. Under Ar atmosphere, MeLi (1.02 M
Et2O solution, 1.50 mL, 1.50 mmol) was added to a mixture of dry
THF (3 mL) and ZnCl2 (1 M THF solution, 0.375 mL, 0.375 mmol) at
0 °C, and the mixture was stirred for 30 min at the temperature.
Preparation of Me3Zn(CN)Li2. Under Ar atmosphere, MeLi (1.02
M Et2O solution, 1.50 mL, 1.50 mmol) was added to a mixture of dry
THF (3 mL) and ZnCl2 (1 M THF solution, 0.375 mL, 0.375 mmol) at
0 °C, and the mixture was stirred at the temperature. The mixture was
cooled to -78 °C and TMSCN (39.2 mg, 0.375 mmol) was added
dropwise to the mixture, and the mixture was stirred at 0 °C for 30
min.
4-Methoxybenzhydrol: mp 64 °C (recrystallized from n-hexane/
ethyl acetate, colorless plates) (lit.40 mp 67-68 °C). 300 MHz 1H NMR
(CDCl3/TMS) δ (ppm): 2.50 (bs, 1H), 3.74 (s, 3H), 5.72 (s, 1H), 6.82
(d, 2H, J ) 8.8Hz), 7.21-7.34 ( m, 7H). MS m/z: 214 (M+).
HRMS: Calcd for C14H14O2: 214.0994. Found: 214.1006.
4-Cyanobenzhydrol (13): mp 64 °C (recrystallized from n-hexane/
ethyl acetate, colorless cubes) (lit.41 mp 67-68 °C); 300 MHz 1H NMR
(CDCl3/TMS) δ (ppm) 3.11 (bs, 1H), 5.79 (1H, s), 7.25-7.35 (5H,
m), 7.47 (2H, d, J ) 8.4Hz), 7.55 (2H, d, J ) 8.4Hz); MS m/z 209
(M+); HRMS calcd for C14H14O2 209.0841, found 209.0829.
4-Acetylbenzhydrol (14): mp 113-114 °C (recrystallized from
1
n-hexane/ethyl acetate, white powder); 300 MHz H NMR (CDCl3/
TMS) δ (ppm) 2.56 (3H, s), 5.87 (1H, s), 7.29-7.36 (5H, m), 7.48
(2H, d, J ) 8.5Hz), 7.91 (2H, d, J ) 8.2Hz); MS m/z 226 (M+ + H);
HRMS calcd for C15H14O2 226.0994, found 226.0994.
1
4-Bromoacetophenone (15): 300 MHz H NMR (CDCl3/TMS) δ
(ppm) 2.59 (3H, s), 7.61 (2H, d, J ) 8.8 Hz), 7.83 (2H, d, J ) 8.8
Hz); MS m/z 198 (M+); HRMS calcd for C15H14O2 197.9680, found
197.9683.
Preparation of n-Butyl 2-Pyridinyl Telluride (19). Under Ar
atomosphere, to a suspension of tellurium powder (273 mg, 214 mmol)
in dry THF (8 mL), n-BuLi (1.39 M, 1.5 mL, 2.09 mmol) was added,
and the mixture was stirred for 10 min. The mixture was cooled to
-78 °C and 2-bromopyridine (317 mg, 2.01 mmol) was added at the
temperature. The mixture was then allowed to warm to ambient
temperature and then refluxed for 92 h. The mixture was diluted with
H2O (50 mL) and extracted with Et2O (50 mL × 3). The ethereal
extract was dried over MgSO4. The solvent was removed, and the
residue was purified by SiO2 column chromatography using n-hexane/
AcOEt (4:1) as a solvent to give n-butyl 2-pyridinyl telluride (19) (368
mg, 70%) as a viscous oil: 300 MHz 1H NMR (CDCl3/TMS) δ (ppm)
0.93 (3H, t, J ) 7.3 Hz), 1.43 (2H, sext, J ) 7.3 Hz), 1.89 (2H, quint,
J ) 7.5 Hz), 3.12 (2H, t, J ) 7.5 Hz), 7.00-7.03 (1H, m), 7.28-7.34
(1H, m), 7.47 (1H, dd, J ) 2.0, 7.7 Hz), 8.47 (1H, dd, J ) 1.1, 4.0
Hz); MS m/z 265 (M+); HRMS calcd for C9H13NTe 265.0111, found
265.0111.
General Procedure for Tellulium-Zinc Exchange Reaction.
Under Ar atmosphere, a THF solution of a zincate (0.57 mmol) was
prepared as described above. The THF solution (0.57 mmol) of the
zincate was cooled to -78 °C and 19 (110 mg, 0.42 mmol) in THF (3
mL) was added dropwise to the mixture. After the mixture was stirred
for specified conditions, benzaldehyde (0.11 mL, 1.0 mmol) was added
to the mixture. After the mixture was stirred for 3 h at room
Preparation of Me3Zn(CN)2Li3 (Zn(CN)2 + 3MeLi). Under Ar
atomosphere, MeLi (1.02 M Et2O solution, 1.10 mL, 1.125 mmol) was
added to a mixture of Zn(CN)2 (44.0 mg, 0.375 mmol) and dry THF
(3 mL) at 0 °C, and the mixture was stirred for 30 min at the
temperature.
Preparation of Me3Zn(SCN)Li2. Under Ar atmosphere, MeLi (1.02
M Et2O solution, 1.50 mL, 1.50 mmol) was added to a mixture of dry
THF (3 mL) and ZnCl2 (1 M THF solution, 0.375 mL, 0.375 mmol) at
0 °C, and the mixture was stirred for 30 min at the temperature. The
mixture was cooled to -78 °C and TMSNCS (49.7 mg, 0.375 mmol)
was added dropwise and the whole was stirred at 0 °C for 30 min.
Preparation of Me3Zn(SCN)2Li3 (Zn(SCN)2 + 3MeLi). Under
Ar atomosphere, MeLi (1.02 M Et2O solution, 1.10 mL, 1.125 mmol)
was added to a mixture of Zn(SCN)2 (73.2 mg, 0.375 mmol) and dry
THF (3 mL) at 0 °C, and the mixture was stirred for 30 min at the
temperature.
General Procedure for Intermolecular Epoxide Opening Reac-
tion. Under Ar atmosphere, a THF solution of a zincates (2 mmol)
was prepared as described above. A solution of 5 (48.1 mg, 0.4 mmol)
in THF (3 mL) was added dropwise to the THF solution of the zincate
(2 mmol) at 0 °C. After allowing to warm to room temperature, the
mixture was stirred for 4 h. The solvent was removed under reduced
pressure and the residue was treated with NH4Cl (30 mL) followed by
extraction with CH2Cl2 (30 mL × 3). The CH2Cl2 layer was dried
over MgSO4, and the CH2Cl2 was removed under reduced pressure.
(39) Wiselogle, F. Y.; Sonneborn, H., III. Organic Synthesis; Wiley: New
York, 1941; Collect. Vol. I, p 90.
(38) Kofron, W. G.; Baclawski, L. M. J. Org. Chem. 1976, 46, 1879.
Watson, S. C.; Eastham, J. F. J. Organomet. Chem. 1967, 9, 165.
(40) Nishida, S. J. Org. Chem. 1967, 32, 2692.
(41) Miller, R. J.; Shechter, H. J. Am. Chem. Soc. 1981, 103, 7329.

New Formulas for Organozincate Chemistry
J. Am. Chem. Soc., Vol. 120, No. 20, 1998 4945
temperature, the solvent was removed under reduced pressure and the
residue was treated with NH4Cl (30 mL) followed by extraction with
CH2Cl2 (30 mL × 3). The CH2Cl2 layer was dried over MgSO4, and
the CH2Cl2 was removed under reduced pressure. The residue was
purified by SiO2 column chromatography using AcOEt/hexane (3:1)
as an eluent to give phenyl(2-pyridinyl)methanol (20) (62.9 mg, 81%)
was removed under reduced pressure and the residue was treated with
NH4Cl (30 mL) followed by extraction with CHCl3 (50 mL × 3). The
CHCl3 layer was dried over MgSO4 and CHCl3 was removed under
reduced pressure. The residue was purified by SiO2 column chroma-
tography using AcOEt/hexane (3:1) as an eluent to give methyl
1-(phenylsulfonyl)indoline-3-acetate (22, X ) NSO2Ph) as a yellow
oil: 300 MHz 1H NMR (CDCl3/TMS) δ (ppm) 2.17 (1H, dd, J ) 16.5,
9.8 Hz), 2.50 (1H, dd, J ) 16.5, 5.2 Hz), 3.46-3.58 (1H, m), 3.65
(1H, dd, J ) 11.0, 5.5 Hz), 3.66 (3H, s), 4.09 (1H, dd, J ) 11.0, 8.8
Hz), 6.97 (1H, t, J ) 6.6 Hz), 7.02 (1H, t, J ) 6.7 Hz), 7.21 (1H, t, J
) 7.2 Hz), 7.43 (2H, t, J ) 7.4 Hz), 7.54 (1H, t, J ) 7.4 Hz), 7.65
(1H, d, J ) 8.5 Hz), 7.78 (2H, d, J ) 5.5 Hz); MS m/z 331 (M+);
HRMS calcd for C17H17NSO4 331.0878, found 331.0868.
1
as a colorless oil: 300 MHz H NMR (CDCl3/TMS) δ (ppm) 5.75
(1H, s), 7.14-7.38 (7H, m), 7.61 (1H, t, J ) 7.3 Hz), 8.54 (1H, d, J
) 4.4 Hz); MS m/z 185 (M+); HRMS calcd for C12H11NO 185.0841,
found: 185.0842.
Preparation of Methyl 4-(2-Iodophenylamino-N-phenylsulfonyl)-
but-2-enoate (21, X ) NSO2Ph). Under Ar atmosphere, pyridine (22.0
g, 275 mmol) and benzenesulfonyl chlolide (11.7 g, 66 mmol) were
added to a THF (5 mL) solution of 2-iodoaniline (12.0 g, 55 mmol) at
0 °C with stirring, and the mixture was stirred at room temperature for
6 h. After evaporation of the solvent, the residue was diluted with
H2O (100 mL) and extracted with CHCl3 (100 × 3). The CHCl3 layer
was dried over MgSO4, and the CHCl3 was removed under reduced
pressure. The solid obtained was recrystallized from ethyl acetate to
give 2-iodo-N-phenylsulfonylaniline (18.0 g, 91%) as a colorless
prisms: mp 113-114 °C (recrystallized from ethyl acetate, colorless
Methyl 2,3-dihydrobenzofuran-3-acetate (22, X ) O): colorless oil;
300 MHz 1H NMR (CDCl3/TMS) δ (ppm) 2.59 (1H, dd, J ) 16.5, 9.5
Hz), 2.80 (1H, dd, J ) 16.5, 5.5 Hz), 3.72 (3H, s), 3.80-3.95 (1H,
m), 4.25 (1H, dd, J ) 9.3, 6.4 Hz), 4.75 (1H, t, J ) 8.1 Hz), 6.80 (1H,
d, J ) 8.1 Hz), 6.86 (1H, t, J ) 7.5 Hz), 7.14 (2H, t, J ) 7.5 Hz); MS
m/z 192 (M+); HRMS calcd for C11H12O3 192.0787, found 192.0803.
Preparation of Allyl 2-Iodophenyl Ether (23). A mixture of
2-iodophenol (0.6 g, 2.7 mmol), allyl bromide (0.7 g, 3 equiv), K2CO3
(1.2 g, 3 equiv), and DMF (20 mL) was stirred at 80 °C for 48 h. After
dilution with Et2O (50 mL), the reaction mixture was washed with water
and brine, dried over MgSO4, and the Et2O was removed under reduced
pressure. The residue was purified by SiO2 column chromatography
using AcOEt/hexane (1:5) as an eluent to give allyl 2-iodophenyl ether
1
prisms); 300 MHz H NMR (CDCl3/TMS) δ (ppm) 7.05 (1H, d, J )
8.0 Hz), 7.13 (1H, t, J ) 8.0 Hz), 7.34 (1H, t, J ) 7.4 Hz), 7.59 (1H,
m), 7.67 (2H, m), 7.91 (1H, d, J ) 8.0 Hz); MS m/z 359 (M+). Anal.
Calcd for C12H10INO2S: C, 40.13; H, 2.81; N, 3.90; S, 8.93. Found:
C, 40.02; H, 2.85; N, 3.89; S, 8.90.
1
(23) (0.70 g, 98%) as a colorless oil: 300 MHz H NMR (CDCl3/
Under Ar atomosphere, to a suspension of sodium hydride (145 mg,
3.6 mmol) in dry THF (5 mL), a THF (5 mL) solution of 2-iodo-N-
phenylsulfonylaniline (1.0 g, 2.78 mmol) was added and stirred for 1
h at room temperature. The mixture was cooled to 0 °C and methyl
4-bromo-2-butenoate (1.0 g, 5.58 mmol) was added at the temperature.
The mixture was then allowed to warm to ambient temperature and
then stirred for 20 h. After reaction, the mixture was diluted with H2O
(50 mL), and the aqueous mixture was extracted with CHCl3 (50 mL
× 3). The CHCl3 layer was dried over MgSO4. The solvent was
removed, and the residue was purified by SiO2 column chromatography
using n-hexane/AcOEt (3:1) as a solvent to give methyl 4-(2-
iodophenylamino-N-phenylsulfonyl)but-2-enoate (21, X ) NSO2Ph):
mp 89.0-89.5 °C (recrystallized from n-hexane/ethyl acetate, white
powder); 300 MHz 1H NMR (CDCl3/TMS) δ (ppm) 3.75 (3H, s), 4.25
(1H, dd, J ) 16.0, 8.0 Hz), 4.40 (1H, dd, J ) 16.0, 8.0 Hz), 5.82 (1H,
d, J ) 16.0 Hz), 6.91 (1H, dt, J ) 15.7, 6.6 Hz), 7.02 (1H, d, J ) 7.7
Hz), 7.09 (1H, d, J ) 8.0 Hz), 7.31 (1H, t, J ) 8.0 Hz), 7.51 (2H, t,
J ) 7.1 Hz), 7.62 (1H, t, J ) 7.1 Hz), 7.88 (1H, d, J ) 8.0 Hz); MS
m/z 457 (M+); HRMS calcd for C17H16NO4SI 456.9844, found
456.9847.
TMS) δ (ppm) 4.60 (2H, d, J ) 5.0 Hz), 5.32 (1H, d, J ) 10.7 Hz),
5.54 (1H, d, J ) 17.3 Hz), 6.00-6.12 (1H, m), 6.72 (1H, t, J ) 7.3
Hz), 6.80 (1H, d, J ) 8.1 Hz), 7.27 (1H, t, J ) 7.3 Hz), 7.78 (1H, d,
J ) 7.6 Hz); MS m/z 260 (M+); HRMS calcd for C11H12O3 259.9698,
found: 259.9711.
Reaction of 23 with Me3ZnLi. Under Ar atmosphere, a THF
solution of a zincates (1.0 mmol) was prepared as described above.
The THF solution of the zincate (1.0 mmol) was cooled to -78 °C,
and 23 (131 mg, 0.5 mmol) in THF (3 mL) was added dropwise to the
mixture. After the mixture was allowed to warm to room temperature,
it was stirred for 48 h. The solvent was removed under reduced
pressure, and the residue was treated with NH4Cl (30 mL) followed
by extraction with CH2Cl2 (50 mL × 3). The CH2Cl2 layer was dried
over MgSO4 and CH2Cl2 was removed under reduced pressure. The
residue was purified by SiO2 column chromatography using AcOEt/
hexane (1:10) as an eluent to give allyl phenyl ether (25) (136.8 mg,
1
quant) as a colorless oil: 300 MHz H NMR (CDCl3/TMS) δ (ppm)
4.5-4.6 (2H, m), 5.2-5.3 (1H, m), 5.3-5.5 (1H, m), 6.0-6.2 (1H,
m), 6.9-7.0 (3H, m), 7.31 (2H, t , J ) 7.5 Hz).
Reaction of 23 with Me4ZnLi2. Under Ar atmosphere, a THF
solution of a zincates (1.0 mmol) was prepared as described above.
The THF solution of the zincate (1.0 mmol) was cooled to -78 °C
and 23 (131 mg, 0.5 mmol) in THF (3 mL) was added dropwise to the
mixture. After the mixture was allowed to warm to room temperature,
it was stirred for 48 h. The solvent was removed under reduced
pressure, and the residue was treated with NH4Cl (30 mL) followed
by extraction with CH2Cl2 (50 mL × 3). The CH2Cl2 layer was dried
over MgSO4, and the CH2Cl2 was removed under reduced pressure.
The residue was purified by SiO2 column chromatography using AcOEt/
hexane (1:5) as an eluent to give 3-methyl-2,3-dihydrobenzofuran (28)
Preparation of Methyl 4-(2-Iodophenyloxy)but-2-enoate (21, X
) O). Under Ar atomosphere, to a suspension of sodium hydride (331
mg, 8.13 mmol) in dry THF (5 mL) was added a THF (5 mL) solution
of 2-iodophenol (1.53 g, 6.25 mmol), and the mixture was stirred for
1 h at room temperature. The mixture was cooled to 0 °C and 4-bromo-
2-butenoate (2.32 g, 12.5 mmol) was added at the temperature. The
mixture was then allowed to warm to ambient temperature and then
stirred for 20 h. The mixture was diluted with H2O (50 mL) and the
aqueous mixture was extracted with CHCl3 (50 mL × 3). The CHCl3
layer was dried over MgSO4. The solvent was removed and the residue
was purified by SiO2 column chromatography using n-hexane/AcOEt
(5:1) as a solvent to give methyl 4-(2-iodophenyloxy)but-2-enoate (1.2
g, 57%) as a colorless oil: 300 MHz 1H NMR (CDCl3/TMS) δ (ppm)
3.78 (3H, s), 4.75 (2H, d, J ) 3.6 Hz), 6.40 (1H, dt, J ) 15.7, 2.2 Hz),
6.74 (1H, d, J ) 7.4 Hz), 6.78 (1H, m), 7.09 (1H, dt, J ) 15.7, 3.6
Hz), 7.30 (1H, t, J ) 8.2 Hz), 7.80 (1H, d, J ) 7.7 Hz); MS m/z 318
(M+); HRMS calcd for C11H11O3I 317.9753, found 317.9757.
General Procedure for Intramolecular Michael Addition Reac-
tion. Under Ar atmosphere, a THF solution of a zincates (0.6 mmol)
was prepared as described above. The THF solution of the zincate
(0.6 mmol) was cooled to -78 °C and 4-(2-iodophenylamino-N-
phenylsulfonyl)but-2-enoate (21, X ) NSO2Ph) (228.6 mg, 0.5 mmol)
in THF (3 mL) was added dropwise to the mixture. The mixture was
stirred at -40 °C for 4 h. The mixture was allowed to warm to room
temperature and was stirred at room temperature for 8 h. The solvent
1
(57.5 mg, 42%) as a colorless oil: 300 MHz H NMR (CDCl3/TMS)
δ (ppm) 1.32 (3H, d, J ) 7.5 Hz), 3.5-3.6 (1H, m), 4.07 (1H, dd, J )
7.4, 8.5 Hz), 4.68 (1H, dd, J ) 8.5, 8.5 Hz), 6.79 (1H, d, J ) 8.5 Hz),
6.87 (1H, t , J ) 8.2 Hz), 7.2-7.1 (2H, m).
N,N-Diallyl-2-iodoaniline (29) was prepared from 2-iodoaniline and
allyl bromide in the same manner as 23. N,N-Diallyl-2-iodoaniline
1
(29): colorless oil; 300 MHz H NMR (CDCl3/TMS) δ (ppm) 3.63
(4H, d, J ) 6.1 Hz), 5.09-5.21 (4H, m), 6.78 (1H, t, J ) 8.0 Hz),
7.02 (1H, d, J ) 8.0 Hz), 6.27 (1H, t, J ) 7.4 Hz), 7.86 (1H, d, J )
8.0 Hz); MS m/z 299 (M+); HRMS calcd for C11H12O3 299.0171, found
299.0154.
1
N-Allyl-3-methylindoline (32): colorless oil, 300 MHz H NMR
(CDCl3/TMS) δ (ppm) 1.31 (3H, d, J ) 6.9 Hz), 2.85 (1H, t, J ) 7.7
Hz), 3.25-3.33 (1H, m), 3.53-3.65 (2H, m), 3.74-3.82 (1H, m), 5.16-

4946 J. Am. Chem. Soc., Vol. 120, No. 20, 1998
Uchiyama et al.
5.31 (2H, m), 5.85-5.96 (1H, m), 6.52 (1H, d, J ) 8.0 Hz), 6.70 (1H,
t , J ) 7.1 Hz), 7.04-7.10 (2H, m); MS m/z 173 (M+); HRMS calcd
for C11H12O3 173.1201, found 173.1203.
7.7, 14.3 Hz), 4.02-4.07 (2H, m), 7.05-7.09 (1H, m), 7.44 (1H, t, J
) 7.7 Hz), 7.53-7.68 (1H, m), 7.71 (1H, dd, J ) 1.8, 7.0 Hz); MS
m/z 289 (M+); HRMS calcd for C15H15NO3S 289.0773, found 289.0784.
X-ray Absorption Measurements and Data Analysis. The EXAFS
experiments were performed by an in-house EXAFS system which has
been described in detail previously.42 Basically it consists of a 12 kW
rotating anode X-ray generator, a spectrometer with a curved Ge(311)
crystal monochromator, and a scintillation counter. The X-ray source
with a silver target was operated at 25 kV to avoid possible
contamination of the third-order reflection. The resolution of the
spectrometer near the Zn absorption edge is about 4 eV with a 200
mm slit used.
Preparation of N-(2,3-Epoxypropyl)-2-iodo-N-phenylsulfonyl-
aniline (33). DEAD (1.13 mL, 7.2 mmol) was added to the mixture
of 2-iodo-N-phenylsulfonylaniline (1.71 g, 4.8 mmol) and PPh3 (1.9 g,
7.2 mmol) in dry THF (10 mL). 2,3-Epoxy-1-propanol (0.48 mL, 7.2
mmol) was added dropwise to the mixture at 0 °C over 10 min. The
mixture was stirred at room temperature for 1 h. After evaporation of
the solvent, the residue was purified by column chromatography using
AcOEt/hexane (2:3) as an eluent to give N-(2,3-epoxypropyl)-2-iodo-
N-phenylsulfonylaniline (33) (1.66 g, 80%): mp 76-77 °C (recrystal-
lized from n-hexane/ethyl acetate, colorless prism); 300 MHz 1H NMR
(CDCl3/TMS) δ (ppm) 2.30 (0.5H, dd, J ) 2.5, 4.7 Hz), 2.42 (0.5H,
dd, J ) 2.5, 4.5 Hz), 2.72 (1H, dt, J ) 4.1, 6.9 Hz), 3.20 (0.5H, bs),
3.32 (0.5H, bs), 3.73 (2H, m), 6.99 (0.5H, dd, J ) 1.6, 8.0 Hz), 7.07
(1H, dt, J ) 0.8, 7.4 Hz), 7.19 (0.5H, dd, J ) 0.8, 7.4 Hz), 7.35 -
7.26 (1H, m), 7.51 (1H, t, J ) 6.6 Hz), 7.62 (1H, t, J ) 7.0 Hz), 7.78
(2H, d, J ) 7.0 Hz), 7.92 (1H, ddd, J ) 1.4, 8.0, 11.8 Hz); MS m/z
415 (M+). Anal. Calcd for C15H14INO3S: C, 43.39; H, 3.40; N, 3.37;
S, 7.72; I, 30.56. Found: C, 43.47; H, 3.45; N, 3.46; S, 7.80; I, 30.61.
General Procedure for Intramolecular Epoxide Opening Reac-
tion. Under Ar atmosphere, a THF solution of a zincate (0.375 mmol)
was prepared as described above. The THF solution of the zincate
(0.375 mmol) was cooled to -78 °C and 33 (104 mg, 0.25 mmol) in
THF (3 mL) was added dropwise to the mixture. After the mixture
was allowed to warm to room temperature, it was stirred for 12 h. The
solvent was removed under reduced pressure, and the residue was
treated with NH4Cl (30 mL) followed by extraction with CH2Cl2 (50
mL × 3). The CH2Cl2 layer was dried over MgSO4 and the CH2Cl2
was removed under reduced pressure. The residue was purified by
SiO2 column chromatography using AcOEt/hexane (2:3) as an eluent
to give a mixture of 1-phenylsulfonylindoline-3-methanol (34) and
3-hydroxy-1-phenylsulfonyl-1,2,3,4-tetrahydroquinoline (35). The ratio
of the two products were determined by analyzing the 1H NMR
spectrum of the mixture and comparing with the authentic samples.
1-Phenylsulfonylindoline-3-methanol (34): colorless oil; 300 MHz 1H
NMR (CDCl3/TMS) δ (ppm) 3.33-3.45 (2H, m), 3.58 (1H, dd, J )
5.1, 10.3 Hz), 3.89 (1H, dd, J ) 5.1, 11.0 Hz), 4.01 (1H, dd, J ) 9.1,
11.0 Hz), 7.01 (1H, t, J ) 7.3 Hz), 7.13 (1H, d, J ) 7.3 Hz), 7.25 (1H,
t, J ) 4.0 Hz), 7.45 (2H, t, J ) 7.7 Hz), 7.55 (1H, t, J ) 7.7 Hz), 7.69
(1H, d, J ) 8.4 Hz), 7.82 (2H, d, J ) 8.4 Hz); MS m/z 289 (M+);
HRMS calcd for C15H15NO3S 289.0773, found 289.0783. 3-Hydroxy-
1-phenylsulfonyl-1,2,3,4-tetrahydroquinoline (35): colorless oil; 300
The EXAFS function ø(k) was subtracted in a manner described in
detail in ref 42 and then was Fourier transformed with a k3 weighing
factor.
Raman Measurements. Raman spectra were excited with the
514.5-nm line of a Coherent Innova 70 argon ion laser using 50 mW
of radiant power at the sample. The spectra were recorded on a Jasco
NR-1800 triple spectrometer equipped with a liquid nitrogen cooled
CCD detector. Samples were kept at 24 °C during the collection of
Raman spectra. Raman frequencies were calibrated using the spectrum
of liquid indene. Wavenumbers of Raman bands were reproducible to
within (0.5 cm-1
.
IR Spectroscopic Analyses. Samples were recorded using a
ReactIR 1000 from ASI Applied Systems fitted with an immerscible
DiComp ATR (Attenuated Total Reflectance) probe optimized for
maximum sensitivity. The spectra were acquired in 128 scans per
spectrum at a gain of 1 and a resolution of 2 using system ReactIR 2.1
software. A representative reaction was carried out as follows: The
IR probe was inserted through a nylon adapter and O-ring seal into an
oven-dried, cylindrical two necked flask fitted with magnetic stir bar.
Following evacuation under full vacuum and flushing with Ar, the flask
was charged with a solution of Me3SiNCS (132 mg, 1.0 mmol) in THF
(1 mL) and cooled in acetone/dry ice bath to -78 °C. Following the
recording of a background spectrum, a 1M THF solution of Me4ZnLi2
(2) (1 mL, 1.0 mmol) was added neat with stirring. IR spectra were
recorded every 4 min over the course of the reaction. To account for
mixing and temperature equilibration, spectra recorded in the first 4
min were discarded. Data manipulation and statistical analyses were
carried out using the system 2.1 ReactIR software.
Acknowledgment. We thank Prof. Dr. Yasuo Udagawa for
helpful discussions of EXAFS, Prof. Dr. Takashi Miura for
useful discussions of Raman, and Mr. Hitoshi Ohfune for
technical assistance of the EXAFS measurements. We are also
grateful to Mr. Manabu Shilai for carrying out a part of
preparation of pyridinyltellurium compounds.
1
MHz H NMR (CDCl3/TMS) δ (ppm) 1.77 (1H, bs), 2.53 (1H, dd, J
) 6.3, 16.2 Hz), 2.77 (1H, dd, J ) 6.0, 15.7 Hz), 3.65 (1H, dd, J )
(42) (a) Tohji, K.; Udagawa, Y.; Kawasaki, T; Masuda, K. ReV. Sci.
Instrum. 1984, 54, 1482. (b) Tohji, K.; Udagawa, Y.; Mizushima, T., Ueno,
A. J. Phys. Chem. 1985, 89, 5671.
JA973855T