Synthesis of 3-hydroxy-2,3,4,5-tetrahydro-3-methyl[1]benzoxepins by ring-closure of isoprenyl terminal epoxides
Abstract
Terminal olefins (13), obtained from reactions oftertiary chlorides (10) with triphenylmethyl-lithium, were converted into epoxides (14); base-induced ring-closure of the latter gave 2-hydroxymethyl-2-methylchromans (15) and 3-hydroxy-2,3,4,5-tetrahydro-3-methyl[1]benzoxepins (17). Dehydration of the tetrahydrobenzoxepin (17a) furnished dihydro[1] benzoxepins.