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

Reactions between 1-(carbamoyl)dichloromethyl radicals and electron-rich alkenes acting as radical accepters are reported for the first time. The intramolecular reaction of trichloroacetamides with silyl enol ethers gives ketones using (TMS)(3)SiH 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.