Studies on the asymmetric reduction of β-oximino methyl ether boronates: reagent control, double diastereocontrol and transmitted remote asymmetric induction
作者:Helen E. Sailes、John P. Watts、Andrew Whiting
DOI:10.1039/b005837h
日期:——
High asymmetric induction (94% ee) could be obtained in the reduction of the achiral E-oxime ether boronate 5 with a homochiral oxazaborolidine 13–BH3–THF complex. Application of this homochiral reducing agent system to non-aromatic oxime ethers 21 produced low to moderate asymmetric induction. Application of the same homochiral reducing agent system to reduction of homochiral boronate E-oximes 3 and
可以通过高手性恶唑硼烷13 -BH 3 -THF络合物还原非手性E-肟醚硼酸酯5获得高不对称诱导(94%ee)。该手性的应用还原剂非芳族肟醚21制产生低到中等的不对称诱导。相同同手性的应用还原剂 系统到 减少 同手性 硼酸盐 E-肟3和4产生了极大的双重非对映选择性效应,即ee分别为8%和95%,这表明适当地选择了“伙伴”分子从硼酸酯基到乙酸酯的远程不对称性是“传递”的。肟 期间 减少。然而,试图获得直接远程不对称诱导在纯手性β-肟基硼酸甲基醚的还原3和4到相应的胺类与Et 3 N–BH 3 –THF混合物(氧化后)产生的零,例如BH 3 –THF络合物,ee高达28%ee硼酸酯 乳沟)。