TY - JOUR
T1 - Asymmetric catalysis with chiral Lewis bases
AU - Denmark, Scott E.
AU - Stavenger, Robert A.
AU - Su, Xiping
AU - Wong, Ken Tsung
AU - Nishigaichi, Yutaka
N1 - Funding Information:
ACKNOWLEDGMENT. We are grateful to the National Science Foundation for generous financial support (CHE 9500397), R.A.S. thanks the Eastman Chemical Co. for a graduate fellowship. Y.N. thanks the Ministry of Education (Japan) for a postdoctoral fellowship.
PY - 1998/8
Y1 - 1998/8
N2 - The trichlorosilyl enolates of methyl ketones, ethyl ketones and cycloalkanones react readily with a variety of aldehydes in aldol addition reactions without external promoters at 0°C - rt. The aldol products are generated in excellent yield and with good to excellent diastereoselectivity (E to syn, Z to anti). In the presence of catalytic amounts (5-15 mol %) of chiral phosphoramide promoters the aldol reactions of enoxytrichlorosilanes now proceed rapidly at -78°C and are extremely diastereoselective (E to anti, Z to syn, 61-99/1). The products are afforded with good to excellent enantioselectivity (anti: 82-97% ee, syn: 58-96% ee).
AB - The trichlorosilyl enolates of methyl ketones, ethyl ketones and cycloalkanones react readily with a variety of aldehydes in aldol addition reactions without external promoters at 0°C - rt. The aldol products are generated in excellent yield and with good to excellent diastereoselectivity (E to syn, Z to anti). In the presence of catalytic amounts (5-15 mol %) of chiral phosphoramide promoters the aldol reactions of enoxytrichlorosilanes now proceed rapidly at -78°C and are extremely diastereoselective (E to anti, Z to syn, 61-99/1). The products are afforded with good to excellent enantioselectivity (anti: 82-97% ee, syn: 58-96% ee).
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U2 - 10.1351/pac199870081469
DO - 10.1351/pac199870081469
M3 - Article
AN - SCOPUS:0001593533
SN - 0033-4545
VL - 70
SP - 1469
EP - 1476
JO - Pure and Applied Chemistry
JF - Pure and Applied Chemistry
IS - 8
ER -