Borinic Acid/Halide Co-catalyzed Semipinacol Rearrangements of 2,3-Epoxy Alcohols
作者:Kashif Tanveer、Seung-Joon Kim、Mark S. Taylor
DOI:10.1021/acs.orglett.8b02248
日期:2018.9.7
A new mode of catalysis of the semipinacol rearrangement of 2,3-epoxy alcohols is described. In combination with a halide salt additive, diarylborinic acids promote a Type II rearrangement that occurs with net retention of configuration. This unusual stereochemical outcome is consistent with a mechanism involving regioselective ring opening of the epoxy alcohol by halide, followed by rearrangement
描述了2,3-环氧醇的半频醇重排催化的新模式。与卤化物盐添加剂结合使用时,二芳基硼酸会促进II型重排,这种重排会净保留构型。这种不寻常的立体化学结果与一种机制有关,该机制涉及通过卤化物使环氧醇的区域选择性开环,然后重排所得的由卤代醇衍生的硼酸酯。该方案适用于多种底物,可实现无环β-羟基羰基化合物的环收缩和扩环以及立体定向合成。