Synthesis of functionalized benzopyrans by sequential [3+3]-cyclization—Williamson reactions of 1,3-bis(trimethylsilyloxy)-7-chlorohepta-1,3-dienes

Functionalized benzopyrans were regioselectively prepared by [3+3]-cyclization of 1,3-bis(trimethylsilyloxy)-7-chlorohepta-1,3-dienes with 3-silyloxy-2-eno-1-ones and subsequent intramolecular Williamson reactions of the salicylates thus formed.