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
(连续处理ë)-Cα,Cβ-disubstltuted Ñ -enoyl磺内酰胺6和13与有机铜试剂(ME 2 CuLi,(CH 2 CH)2 CuLi中,Ph 2 CuLi在PBU的存在3或SCN - )和水 NH 4 Cl分别给出产物7和14。结晶和轻度皂化7→11和14→15提供了对映体纯的羧酸,其中包含两个新的立体异构中心。假定的反应拓扑结构通过瞬态“ nolate”(22→23)的乙酰基酮得到支持,并与相关的有机镁添加/质子化序列进行了比较。