Upon exposure of acrylic ester 1 to alcohols 2a-i in the presence of a cyclometalated iridium catalyst modified by (-)-TMBTP, catalytic C-C coupling occurs, providing enantiomerically enriched 5-substituted α-exo-methylene γ-butyrolactones 3a-i. Bromination of the methylene butyrolactone products followed by zinc-mediated reductive aldehyde addition provides the disubstituted α-exo-methylene γ-butyrolactones
当
丙烯酸酯1在(-)-
TMBTP改性的环
金属化
铱催化剂存在下暴露于醇2a-i时,发生催化CC偶联,提供对映体富集的5-取代的α-外型-亚甲基
γ-丁内酯3a-i。亚甲基丁内酯产物的
溴化随后通过
锌介导的还原醛加成提供了具有良好至优异
水平的非对映选择性的二取代的α-外型-亚甲基
γ-丁内酯6a和6b。