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