Radical promoted cyclisations of trichloroacetamides with silyl enol ethers and enol acetates: the role of the hydride reagent [tris(trimethylsilyl)silane vs. tributylstannane

Abstract

Reactions between 1-(carbamoyl)dichloromethyl radicals and electron-rich alkenes acting as radical acceptors are reported for the first time. The intramolecular reaction of trichloroacetamides with silyl enol ethers gives ketones using (TMS)3SiH as the mediator, and alcohols when using Bu3SnH. The reaction with enol acetates gives acetates using either of the above hydride reagents. These radical processes have been applied to the synthesis of 2-azabicyclo[3.3.1]nonanes.