The direct bradsher reaction. Part III. A new method for the benzologation of heterocycles

Abstract

The action of dichloromethyl alkyl ethers and tin(IV) chloride on 2-(allyl- or substituted allyl)benzo[b]thiophens or benzo[b]furans gives rise to the corresponding unsubstituted or 3-substituted derivatives of dibenzothiophen or dibenzofuran. In particular, the use of ethyl dichloro(ethoxy)acetate gives derivatives containing a 1-ethoxycarbonly substituent. A range of novel 1-substituted dibenzothiophens has thus been prepared.