Ynolates were found to react with alpha-alkoxy-, alpha-siloxy-, and alpha-aryloxyketones at room temperature to afford tetrasubstituted olefins with high Z selectivity. Since the geometrical selectivity was determined in the ring opening of the beta-lactone enolate intermediates, the torquoselectivity was controlled by the ethereal oxygen atoms. From experimental and theoretical studies, the high Z
Chelates as intermediates in nucleophilic additions to alkoxy ketones according to Cram's rule (cyclic model)
作者:Xiangning Chen、Edwin R. Hortelano、Ernest L. Eliel、Stephen V. Frye
DOI:10.1021/ja00031a036
日期:1992.2
Chelates have been considered intermediates in the often highly stereoselective reactions of α-alkoxy and similarly substituted ketones for over 30 years, 10 but without mechanistic evidence