Practical asymmetric synthesis of both erythro and threo aldols based on the MABR-Promoted selective rearrangement of erythro and threo epoxy silyl ethers: unusual effect of silyl substituents
作者:Keiji Maruoka、Junko Sato、Hisashi Yamamoto
DOI:10.1016/s0040-4020(01)92266-5
日期:1992.1
with the electronic effect of silyl substituents rather than their steric effect, and the more electron-withdrawing triphenylsilyl group exhibits better selectivity than trialkylsilyl group. Since enantiomeric erythro and threo epoxy silyl ethers are readily accessible by Sharpless asymmetric epoxidation, this method allows the practical asymmetric synthesis of four possible aldol isomers with high selectivity
基于光学活性的苏式和赤式环氧甲硅烷基醚各自的立体控制重排,并化学计量地使用了体积特别大的,亲氧性的甲基铝双(4-bromo-2 ),开发了一种新的不对称合成的赤型和苏型醛醇(β-甲硅烷醛)。,6-二叔丁基苯氧化物(MABR)在温和的条件下。观察到的立体选择性随甲硅烷基取代基的电子效应而不是其空间效应而变化,并且吸电子更多的三苯基甲硅烷基比三烷基甲硅烷基具有更好的选择性。由于对映异构的赤型和苏式 夏普不对称不对称环氧化很容易获得环氧甲硅烷基醚,这种方法可以实际不对称地以高选择性合成四种可能的羟醛异构体。