Diastereoselective Aldol Additions of Chiral β-Hydroxy Ethyl Ketone Enolates Catalyzed by Lewis Bases
作者:Scott E. Denmark、Shinji Fujimori
DOI:10.1021/ol026593v
日期:2002.10.1
trichlorosilyl enolates derived from chiral ethyl ketones bearing a beta-hydroxyl group and an alpha-stereogenic center were employed in the phosphoramide-catalyzed aldol reaction. The addition of Z-enolates to achiral aldehydes produced aldol products in good yields and high syn relative diastereoselectivities. The internal diastereoselectivity is controlled by the catalyst configuration, allowing for
Lewis Base Catalyzed Aldol Additions of Chiral Trichlorosilyl Enolates and Silyl Enol Ethers
作者:Scott E. Denmark、Shinji Fujimori、Son M. Pham
DOI:10.1021/jo051930+
日期:2005.12.1
diastereodifferentiation in chiral Lewis base catalyzed aldoladditions using chiral enoxysilanes derived from lactate, 3-hydroxyisobutyrate, and 3-hydroxybutyrate have been investigated. Trichlorosilylenolates derived from the chiral methyl and ethyl ketones were subjected to aldolization in the presence of phosphoramides, and the intrinsic selectivity of these enolates and the external stereoinduction