Phase-Transfer Synthesis of Optically Pure Oxetanes Obtained from 1,2,2-Trisubstituted 1,3-Propanediols
作者:Hu Xianming、Richard M. Kellogg
DOI:10.1055/s-1995-3939
日期:1995.5
Treatment of the 3-monomethanesulfonates of 1,2,2-trisubstituted 1,3-propanediols under phase-transfer conditions affords 2-aryl (or alkyl)-3,3-dialkyloxetanes. Twelve oxetanes have been obtained by this method; three of these oxetanes have been obtained enantiomerically pure as both enantiomers starting from the appropriate enantiomerically pure 1,3-diols. In these reactions the chiral center does not undergo inversion and the oxetanes have the same absolute configuration as the starting 1,3-diols.
Acid catalyzed ring-opening reactions of optically pure 2-aryl-3,3-dimethyloxetanes
作者:Hu Xianming、Richard M. Kellogg
DOI:10.1016/0957-4166(95)00173-m
日期:1995.6
Some ring-opening reactions of optically pure 2-aryl-3,3-dimethyl oxetanes have been examined under strongly protic or Lewis acid conditions. Ring-opening occurred at the benzylic position and partial inversion of configuration was observed in the case of hydrolysis or alcoholysis of the optically pure oxetanes catalyzed by H2SO4. The acid concentration affects the degree of inversion of configuration
已经在强质子或路易斯酸条件下检查了光学纯的2-芳基-3,3-二甲基氧杂环丁烷的一些开环反应。在H 2 SO 4催化的光学纯的氧杂环丁烷的水解或醇解的情况下,在苄基位置发生开环并且观察到构型的部分反转。酸浓度影响水或甲醇中构型的转化程度。在路易斯酸(BF 3醚)的辅助下,与正丁基锂或硫醇锂反应,得到相应的β-取代的苄醇。现在取代发生在受阻最少的碳原子上,不对称中心的构型不受影响。
Near absolute regio-, diastereo-, and enantioselectivity in a palladium: Catalyzed alkylation using an uncommon chiral auxiliary
作者:Ronald Sjouken、Rijko Ebens、Richard M. Kellogg
DOI:10.1002/recl.19921110107
日期:——
R-(+)-1-(2-chlorophenyl)-2,2-dimethyl-propan-1,3-diol (2) with a derivative (1) of 1-formylcyclohexene substituted in the 3-position with an acetoxy group proceeded with absolute stereospecificity at the acetal center. Catalytic alkylation of the π-allyl complex obtained upon reaction with Pd with the anion of dimethylmalonate proceeded at the 3-position of the cyclohexyl ring with complete stereocontrol