Stereoselective conjugate addition of lithium and titanium enolates to γ - alkoxy enones
作者:Anna Bernardi、Chiara Marchionni、Barbara Novo、Katia Karamfilova、Donatella Potenza、Carlo Scolastico、Pietro Roversi
DOI:10.1016/0040-4020(96)00028-2
日期:1996.3
The addition of titanium and lithium enolates 1 and 2 to γ-alkoxy enone 4 occurs in good yield with good stereoselectivities. 3,4 syn - 2,3 syn adducts 7 are obtained starting from the lithium enolate 2, whereas the 3,4 syn - 2,3 anti isomers 9 are formed using the titanium enolate 1. The levels of selectivity vary with the nature of the oxygen protecting group.
向γ-烷氧基烯酮4中加入
钛和烯醇
锂1和2的产率高,立体选择性好。从烯醇
锂2开始获得3,4同-2,3同加合物7,而使用烯醇
钛1形成3,4同-2,3反异构体9。选择性
水平随氧保护基的性质而变化。