Heteroaryl radicals. Part 1. Synthesis of linear pyridine-fused ring systems by endo-selective 2-pyridyl radical cyclizations

摘要

Bu3SnH-induced 2-pyridyl radicals, derived from the 2-bromopyridinyl-substituted methylenecyclohexane 4nand also the vinyl- and the allyl-cyclohexanols 5 and 6, undergo endo-selective cyclizations to give six-, seven- andneight-membered-ring annulated pyridines 7, 11 and 12.