Preparation of Some 6-Substituted 2,2-Dimethyl- and 2,2- and 2,4-Diphenyl-naphtho[1,2-b]pyrans

Abstract

6-Chloro-, 6-bromo-, and 6-methyl-2,2-dimethyl-, and -2,2- and -2,4-diphenyl-naphtho[1,2-b]pyrans are prepared from the appropriate 4-substituted 2H-naphtho[1,2-b]pyran-2-ones and either methylmagnesium iodide or phenylmagnesium bromide; some related compounds and derivatives are also prepared and dimerisation of cylized products from the methylmagnesium iodide reactions affords dimers including a relative of isolapachenole through addition reactions of the intermediate carbonium ion.