The opposite diastereoselectivity in the alkylation and protonation of enolates
作者:Yoshinori Yamamoto、Kazuhiro Maruyama
DOI:10.1039/c39840000904
日期:——
enoate (5) produces predominantly the syn-isomer (7) having the butyl and methyl groups syn on the carbon chain, while the methylation of the enolate derived from the ester (8) gives preferentially the other diastereoisomer, anti-(6); the diastereoselectivity can be explained by an eclipsed model.
Optically active compound, antiferroelectric liquid crystal composition containing the same, process for producing the same and process for producing optically active carboxylic acid
申请人:Takasago International Corporation
公开号:EP0884309A1
公开(公告)日:1998-12-16
Disclosed is a novel optically active compound which exhibits no antiferroelectric liquid crystal phase but can be incorporated in an antiferroelectric liquid crystal having a high threshold voltage to reduce the threshold voltage thereof, an antiferroelectric liquid crystal composition containing the compound, a process for the reduction of the threshold voltage of an antiferroelectric liquid crystal composition, a process for producing the compound and a process for producing an optically active carboxylic acid as an intermediate.
OPPOLZER, WOLFGANG;KINGMA, AREND J.;POLI, GIOVANNI, TETRAHEDRON, 45,(1989) N, C. 479-488
作者:OPPOLZER, WOLFGANG、KINGMA, AREND J.、POLI, GIOVANNI
DOI:——
日期:——
US5965059A
申请人:——
公开号:US5965059A
公开(公告)日:1999-10-12
Asymmetric 1,4-additions of gilman reagents to α,β - disubstitoted (e)-enoylsultams / “enolate” protonations
作者:Wolfgang Oppolzer、Arend J. Kingma、Giovanni Poli
DOI:10.1016/0040-4020(89)80075-4
日期:1989.1
Successive treatment of (E)-Cα,Cβ-disubstltuted N-enoyl sultams 6 and 13 with organocopper reagents (Me2CuLi, (CH2CH)2CuLi, Ph2CuLi in the presence of PBu3 or SCN−) and aq. NH4Cl gave products 7 and 14. respectivety, with good to excellent stereoface differentiation at Cβ and Cα. Crystallization and mild saponification 7 → 11 and 14 → 15 furnished enantiomerically pure carboxylic acids containing