A One-Pot Method to Prepare 4,5-Benzotropones and 2,3,4,5-Dibenzotropones

Abstract

An extremely simple method was developed to prepare 4,5-benzotropones & 2,3,4,5-dibenzotropones through one-pot cycloaddition reaction of alkynes with naphthoquinones and dibenzoquinones via BF3.Et2O mediation, in which, various mono- or disubstituted phenylacetylenes, multisubstituted 1,2-naphthoquinones and dibenzoquinone substrates were investigated. In addition, a scale-up synthesis of dibenzotropone 3a and further derivation of dibenzotropone 3f were explored.