Stereoseletive Reduction of<i>β</i>-Hydroxy Ketones to 1,3-Diols with the Aid of a Terphenylboronic Acid
作者:Hiroshi Yamashita、Koichi Narasaka
DOI:10.1246/cl.1996.539
日期:1996.7
stereoselective reduction of acyclic and cyclic β-hydroxy ketones. The terphenylboronic acid 1 and acyclic β-hydroxy ketones 2 are converted to the corresponding boronates by azeotropic removal of water. The resulting boronates are treated in situ with reducing reagents to give syn 1,3-diols 3 almost exclusively. Anti α-substituted β-hydroxy ketones 8 are also reduced to give anti, anti 1,3-diol 9 stereoselectively
1-Hydroxy-6,8-diphenyl-1,2,3,4-tetrahydro-2-oxa-1-boranaphthalene(三联苯硼酸 1)用于立体选择性还原无环和环状 β-羟基酮。三联苯硼酸 1 和无环 β-羟基酮 2 通过共沸去除水转化为相应的硼酸酯。所得硼酸酯用还原剂原位处理以几乎完全得到syn 1,3-二醇3。抗 α-取代的 β-羟基酮 8 也被还原以立体选择性地产生抗、抗 1,3-二醇 9。此外,3-羟基-1-环戊酮的还原以高选择性得到顺式二醇11。