Diastereoselective Electrophilic Fluorination of Enantiopure α-Silylketones Using N-Fluoro-benzosulfonimide: Regio- and Enantioselective Synthesis of α-Fluoroketones

Abstract

α-Fluoroketones 6 are synthesized in good yields and high enantiomeric excesses (ee = 87- ≥96%) from the corresponding simple cyclic and acyclic ketone precursors. The procedure involves a regio- and diastereoselective electrophilic fluorination of enantiopure α-silylketones 2 (de = 37-≥ 98%) using commercially available N-fluorobenzosulfonimide as fluorinating agent, followed by a racemization-free cleavage of the silyl directing group with almost quantitative yields.

Key words

asymmetric synthesis - SAMP/RAMP hydrazones - α-silylketones - electophilic fluorination - α-fluoroketones

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16

The configuration assignments for linear α-fluoro-α"-silylketones and as a consequence the configuration of the acyclic α-fluoroketones were erroneously wrong in our preliminary communication.