Oxidative radical cyclization on enamide systems using n-Bu3SnH and dilauroyl peroxide

Efficient 5-endo and 6-endo oxidative radical cyclizations on enamide systems are described using nBu₃SnH and dilauroyl peroxide both as initiator and oxidant. Dibenzoyl peroxide and dicumyl peroxide were also tested in the same reaction and the product yields were very similar to those obtained with dilauroyl peroxide. The erythrina ring system was constructed in a two-step sequence featuring this novel process.