Synthesis of Enantioenriched Fluorinated Enol Silanes Enabled by Asymmetric Reductive Coupling of Fluoroalkylacylsilanes and 1,3-Enynes and Brook Rearrangement
Xiaowu Fang, Songwei Wen, Peishen Jin, Wenjing Bao, Shanshan Liu, Hengjiang Cong, Xiao Shen
Abstract
Fluorinated enol silanes are broadly useful in various synthetic transformations such as Mukaiyama aldol, Michael, and Mannich reactions. However, previous methods to these intermediates are limited to racemic synthesis. Therefore, the development of access to enantioenriched ones is of great value. We now describe an enantioselective reductive coupling reaction of fluoroalkylacylsilanes and 1,3-enynes. The coupling products were easily transformed to fluorinated enol silanes with the retention of enantiopurity though Brook rearrangement. The practicality of our methodology was demonstrated by the multisteps-one-isolation processes for the synthesis of alkynyl, alkenyl, and alkyl substituted enantioenriched β,β-difluoro enol silanes. The applications of the enantiopure β,β-difluoro enol silane in the synthesis of valuable chiral organofluorine compounds demonstrated the synthetic potential of our reaction.