New type of a stable p-quinone methide possessing a pendant malonate moiety: synthesis and reactions with C-nucleophiles

Cyclopropanation of 2,6-di-tert-butyl-4-vinylphenol with diazomalonates affords 4-hydroxyaryl-substituted cyclopropane dicarboxylates prone to easy ring opening into p-quinone methides tethered to malonate unit. The resulting quinone methides react with various C-nucleophiles to form the corresponding adducts thus serving as synthetic equivalents for donor-acceptor cyclopropanes in the homo-Michael addition. Side processes, namely, isomerization and dimerization of the quinone methides under basic conditions, were found.