SYNTHESIS OF ISOTHIOCHROMENES AND 1,3-DIHYDROBENZOcTHIOPHENES BY IODINE- AND HYDROBROMIC ACID-MEDIATED CYCLIZATIONS OF o-(tert-BUTYLSULFANYL)METHYL)STYRENES

摘要

Methods for the syntheses of 4-substituted isothiochromenes and 1,1-disubstituted 1,3-dihydrobenzocthiophenes have been developed. Thus, treatment of alpha-substituted o-(tert-butylsulfanyl)methylstyrenes, derived from alpha-substituted o-bromostyrenes using an easily operated four-step sequence, with iodine in the presence of sodium hydrogencarbonate gave isothiochromene derivatives. These tert-butyl sulfides were treated with concentrated hydrobromic acid to give 1,3-dihydrobenzocthiophene derivatives.