RCH(OMEM)CFBr2 with n-BuLi at −130 °C in the presence of 4-heptanone gives the corresponding adduct diastereoselectively. The stereochemical outcome is explained in terms of the chelation between lithium and oxygen atoms of the MEM group. Starting with 2-phenylpropanal, a product is produced highly selectively containing three contiguous stereocenters including a -CFBr- moiety.
在
4-庚酮存在下,在-130°C下用n -BuLi处理RCH(OM
EM)CFBr 2产生非对映选择性。根据M
EM基团的
锂和氧原子之间的螯合解释了立体
化学结果。从
2-苯基丙醛开始,高度选择性地产生包含三个连续的立体中心的产物,包括-CFBr-部分。