1
2
1694 J. Am. Chem. Soc., Vol. 119, No. 48, 1997
Communications to the Editor
-fold rotation axis symmetry, refinement of the crystallographic
to our structural results is the observation by Hogeveen and
data indicated disorder in the final model of the alkyl groups
of 5 and 6 which incorporate 2-fold rotation axial symmetry.
Eleveld of enantioselective addition of n-BuLi to benzaldehyde
1
1
15
in the presence of chiral lithium amides in a variety of solvents.
Several excellent reviews of enantioselective additions of
organometallic reagents to carbonyl compounds have been
It is noteworthy that the ratio of n-BuLi to chiral amide ligand
utilized by Hogeveen was 2.7:4 and not 1:1. It is also
noteworthy that the best selectivity in this study (90% ee) was
observed with a chiral Li amide ligand derived from an
O-methyl-R-amino alcohol which closely resembles 1. While
we are not yet willing to conclude that complexes with structures
similar to 4-6 are responsible for Hogeveen’s results, the
reagent stoichiometry and the ligand similarity indicate that this
is certainly not unreasonable.
A different structure was assigned by Hilmersson and
Davidsson to the complex between a chiral lithium amide and
n-BuLi in diethyl ether solution. These investigators conclude
that a 1:1 complex of the chiral lithium amide/n-BuLi coexists
with n-BuLi tetramer in solution from their NMR studies.16 We
are currently investigating the relationship between our chiral
1
2
published. Most examples cited report the use of uncharged
chiral ligands or of chiral lithium alkoxides complexed with
13
organometallic reagents to induce enantioselectivity. Several
examples of the use of alkyllithium/sparteine reagents are also
noteworthy for their stereoselectivity.14 Particularly relevant
(4) (a) Toriyama, M.; Sugasawa, K.; Shindo, M.; Tokutake, N.; Koga,
K. Tetrahedron Lett. 1997, 38, 567-70. (b) Asami, M. J. Syn. Org. Chem.
Jpn. 1996, 54, 188-199. (c) Bhuniya, D.; Dattagupta, A.; Singh, V. K. J.
Org. Chem. 1996, 61, 6108-6113. (d) Ruck, K. Angew. Chem., Int. Ed.
Engl. 1995, 34, 433-5. (e) Landais, Y.; Ogay, P. Tetrahedron-Assym. 1994,
5
, 541-4. (f) Bhuniya, D.; Singh, V. K. Syn. Commun. 1994, 24, 375-85.
(
g) Juaristi, J.; Beck, A. K.; Hansen, J.; Matt, T.; Mukhopadhyay, T.;
Simson, M.; Seebach, D. Synthesis 1993, 12, 1271-90. (h) Bunn, B. J.;
Simpkins, N. S.; Spavold, Z.; Crimmin, M. J. J. Chem. Soc., Perkin Trans.
1
1993, 3113-6. (i) Edwards, A. J.; Hockey, S.; Mair, F. S.; Raithby, P.
R.; Snaith, R. J. Org. Chem. 1993, 58, 6942-3. (j) Sato, D.; Kawasaki, H.;
Shimada, I.; Arata, Y.; Okamura, K.; Date, T.; Koga, K. J. Am. Chem.
Soc. 1992, 114, 761-3. (k) Cox, P. J.; Simpkins, N. S. Tetrahedron-Asymm.
2
:1 amide/alkyllithium complexes and the 1:1 complexes
reported by these authors as well as the stereoselectivity in
carbonyl additions of the alkyl group from the complexes 4-6
which we have characterized.
1
991, 2, 1-26. (l) Urabe, H.; Yamakawa, T.; Sato, F. Tetrahedron Asymm.
992, 3(1), 5-8. (m) Leonard, J.; Hewitt, J. D.; Ouali, D.; Simpson, S. J.;
1
Newton, R. F. Tetrahedron Lett. 1990, 31, 6703-6706. (n) Cain, C. M.;
Cousins, R. P. C.; Coumbarides, G.; Simpkins, N. S. Tetrahedron 1990,
Acknowledgment. This work was supported by the National
Institutes of Health through grant GM-35982. The X-ray diffraction
equipment was originally purchased with assistance from the National
Science Foundation and upgraded with assistance from the National
Institutes of Health. We thank Prof. Gene B. Carpenter for helpful
discussions concerning the interpretation of the X-ray diffraction data.
This paper is dedicated to Professor Dieter Seebach on the occasion of
his 60th birthday.
4
6, 523-544. (o) Asami, M. Bull. Chem. Soc. Jpn. 1990, 63, 721-727.
(
p) Barr, D.; Berrisford, D. J.; Jones, R. V. H.; Williams, D. J.; Slawin, A.
M. Z.; Snaith, R.; Stoddart, J. F. Angew. Chem., Int. Ed. Engl. 1989, 28(8),
1
044-7. (q) Simpkins, N. S. Chem. Ind. 1988, 387-389. (r) Muraoka, M.;
Kawasaki, H.; Koga, K. Tetrahedron Lett. 1988, 29(3), 337-8. (s) Duhamel,
L.; Davoust, D.; Plaquevent, J. C.; Ravard, A. Tetrahedron Lett. 1987, 28,
5
6
1
1
1
1
1
7
517-5520. (t) Ando, A.; Shioiri, T. J. Chem. Soc., Chem. Commun. 1987,
56-658. (u) Reetz, M. T.; Kukenhohner, T.; Weinig, P. Tetrehedron Lett.
986, 27(47), 5711-4. (v) Eleveld, M. B.; Hogeveen, H. Tetrahedron Lett.
986, 27, 631-634. (w) Hogeveen, H.; Menge, W. M. P. Tetrahedron Lett.
986, 27, 2767-70. (x) Simpkins, N. S. J. Chem. Soc., Chem. Commun.
986, 88-90. (y) Shirai, R.; Koga, K.; Tanaka, M. J. Am. Chem. Soc. 1986,
08, 543-545. (z) Whitesell, J. K.; Felman, S. W. J. Org. Chem. 1980, 45,
55-6.
Supporting Information Available: Tables of crystallographic
data, atomic numbering schemes, thermal ellipsoid plots, atomic position
and thermal parameters, and bond lengths and bond angles for
complexes 4-6 (24 pages). See any current masthead page for ordering
and Internet access instructions.
(5) (a) Shirai, R.; Sato, D.; Aoki, K.; Tanaka, M.; Kawasaki, H.; Koga,
K. Tetrahedron 1997, 53(17), 5963-72. (b) Ando, A.; Shiroiri, T.
Tetrahedron 1989, 45(16), 4969-88. (c) Ando, A.; Shiroiri, T. J. Chem.
Soc., Chem. Commun. 1987, (9), 656-8.
JA972277D
(
6) (a) Veith, M.; Boehnlein, J. Chem. Ber. 1989, 122, 603-7. (b) Veith,
(11) The crystallographic 2-fold rotation symmetry requirement is
satisfied for the sec-butyl complex 5 by a model with the carbanionic carbon
atom located on the symmetry axis, the sec-butyl group adopts an s-cis
conformation and partial occupancy/exchange of the methyl and ethyl groups
about the carbanionic center and for the tert-butyl complex 6 by a model
with the carbanionic center located on the symmetry axis and a disorder by
a rotation of the tert-butyl group by 60° around the symmetry axis. Only
one of the two occupied sites in both 5 and 6 is depicted in Figure 1 for
clarity. The largest peaks and holes in the final electron density maps of 5
M.; Boehnlein, J.; Huch, V. Chem. Ber. 1989, 122, 841-9.
(7) Hilmersson, G.; Davidsson, O¨ . J. Org. Chem. 1995, 60, 7660-9.
8) (a) Williard, P. G.; Salvino, J. M. J. Org. Chem. 1993, 58(1), 1-3.
(
(
b) See, also: Edwards, A. J.; Hockey, S.; Mair, F. S.; Raithby, P. R.; Snaith,
R. J. Org. Chem. 1993, 58(25), 6942-3. (c) Kim, Y. J.; Bernstein, M. P.;
Roth, A. S. G.; Romesberg, F. E.; Williard, P. G.; Fuller, D. J.; Harrison,
A. T.; Collum, D. B. J. Org. Chem. 1991, 56, 4435-9. (d) Galiano-Roth,
A. S.; Kim, Y. J.; Gilchrist, J. H.; Harrison, A. T.; Fuller, D. J.; Collum, D.
B. J. Am. Chem. Soc. 1991, 113, 5053-5. (e) Galiano-Roth, A. S.; Collum,
D. B. J. Am. Chem. Soc. 1989, 111, 6772-8.
-
3.
and 6 are less than 0.13 eÅ
(12) (a) Koga, K. Pure Appl. Chem. 1994, 66(7), 1487-92. (b) Soai,
K.; Niwa, S. Chemical ReV. 1992, 92(5), 833-56. (c) Noyori, R.; Kitamura,
M. Angew. Chem., Int. Ed. Engl. 1991, 30, 49-69. (d) Tomioka, K.
Synthesis 1990, 7, 541-9. (e) Koga, K. J. Syn. Org. Chem. Jpn. 1990, 48,
463-75. (f) Whitesell, J. K. Chem. ReV. 1989, 89(7), 1581-90. (g) Seebach,
D. Angew. Chem., Int. Ed. Engl. 1988, 27, 1624-54. (h) Evans, D. A.
Science 1988, 240, 420.
(
9) Crystallizations are optimized to produce diffraction quality samples
and not necessarily to obtain maximum yields.
(
10) X-ray diffraction data were recorded at -40 °C on a Siemens four-
circle diffractometer with a SMART CCD detector. The structures solved
routinely with SHELX direct methods and were refined utilizing full matrix
2
least squares on F . Crystallographic parameters for each compound are
summarized as follows. (a) Compound 4 crystallized from heptane solution
in the monoclinic space group P21 with unit cell parameters, a ) 18.206(3)
Å, b ) 8.869(10) Å, c ) 18.555(3) Å, a ) γ ) 90°, and â ) 113.35(10)°.
Of the diffraction data (12 249 reflections) recorded, a total of 7164
independent reflections with Rint ) 0.029 were utilized in refinement of
(13) For recent examples, see: (a)Thompson, A. S.; Corley, E. G.;
Huntington, M. F.; Grabowski, E. J. J. Tetrahedron Lett. 1995, 36, 8937-
40. (b) Huffman, M. A.; Yasuda, N.; DeCamp, A. E.; Grabowski, E. J. J.
J. Org. Chem. 1995, 60, 1590-4. (c) Ye, M.; Logaraj, S.; Jackman, L. M.;
Hillegass, K.; Hirsh, K.; Bollinger, A. M.; Grosz, A. L.; Mani, V.
Tetrahedron 1994, 50, 6109-16.
5
36 parameters. The final model resulted in the following statistical
parameters: GOOF ) 1.016, R(all data) 0.046 and wR2(all data) ) 0.1158.
b) Compound 5 crystallized from heptane solution in the tetragonal space
group P43212 with unit cell parameters, a ) b ) 8.810(10) Å, c )
(14) ) (a) Wu, S.; Lee, S.; Beak, P. J. Am. Chem. Soc. 1996, 118(4),
715-21. (b) Beak, P.; Kerrick, S. T.; Wu, S.; Chu, J. J. Am. Chem. Soc.
1994, 116, 3231-9. (c) Hoppe, D.; Hintze, F.; Tebben, P.; Paetow, M.;
Ahrens, H.; Schwerdtfeger, J.; Sommerfeld, P.; Haller, J.; Guarnieri, W.;
Kolczewski, S.; Hense, T.; Hoppe, I. Pure Appl. Chem. 1994, 66, 1479-
86. (d) Gallagher, D. J.; Kerrick, S. T.; Beak, P. J. Am. Chem. Soc. 1992,
114, 5872-3. (e) Kerrick, S. T.; Beak, P. J. Am. Chem. Soc. 1991, 113,
9708-10. (f) Hoppe, D.; Hintze, F.; Tebben, P. Angew. Chem., Int. Ed.
Engl. 1990, 29, 1422-4. (g) Hoppe, D.; Carstens, A.; Kr a¨ mer, T. Angew.
Chem., Int. Ed. Engl. 1990, 29, 1424-5.
(
3
4.620(10) Å, a ) â ) γ ) 90°. Of the diffraction data (12 376 reflections)
recorded, a total of 1943 independent reflections with Rint ) 0.0495 were
utilized in refinement of 146 parameters. The final model resulted in the
following statistical parameters: GOOF ) 1.159, R(all data) 0.056 and wR2-
(
all data) ) 0.143. (c) Compound 6 crystallized from pentane solution in
the monoclinic space group P43212 with unit cell parameters, a ) b )
.971(10) Å, c ) 33.758(8) Å, a ) â ) γ ) 90°. Of the diffraction data
12 138 reflections) recorded, a total of 1914 independent reflections with
8
(
(15) Eleveld, M. B.; Hogeveen, H. Tetrahedron Lett. 1984, 25(45), 5187-
90.
Rint ) 0.071 were utilized in refinement of 146 parameters. The final model
resulted in the following statistical parameters: GOOF ) 1.026, R(all data)
0
(16) Hilmersson, G.; Davidsson O¨ . J. Organomet. Chem. 1995, 489,
175-9.
.068 and wR2(all data) ) 0.146.