A novel route to functionalized linearly benzannulatedmedium ring carbocyclics through regioselective aryl radical cyclization

摘要

A new synthesis of 2 , 2 - dimethyl - 12 - [ 3 - methylbut - 2 - enyl ] - 2H , 6H - pyrano [ 3 , 2 - b ] xanthen - 6 - one (7) is described from 1 , 3 - dihydroxyxanthone and involved the preparation of a linear dihydropyranoxanthone (26), its conversion