Syntheses and reactions of spirocyclopropaneanthrones. Part 1. Reactions of p-diazo-ketones with p-quinone methides

Abstract

The carbenic reaction of 10-diazoanthrone (1) with 10-methyleneanthrone (2) gave dispiro[anthrone-10, 1′-cyclopropane-2′, 10″-anthrone](3), which thermally rearranged with synchronous ring expansion, yielding spiro[2H-aceanthrone-2, 10′-anthrone](7). Similar reactions of diazonaphthalen-1 (4H)-one (11) with the quinone methide (2) and of the diazo-ketone (1) with 2, 6′-di-t-butyl-4-methylenecyclohexa-2, 5-dien-1-one (16) afforded directly the rearrangement product, 10-hydroxytribenz[a, de, j]anthracen-5-one (12), and the cyclopropyl ring-opening product, 10-(4-hydroxy-3, 5-di-t-butylbenzyl)anthrone (17), respectively, instead of the dispiro-compounds.