Overcrowded molecules. Part 17. Thermal reactions of (α-phenylethylidene)(substituted methylene)succinic anhydrides

Abstract

The thermal E–Z isomerisation and electrocyclic reactions of diphenylmethylene-, benzylidene-, and isopropylidene(α-phenylethylidene)succinic anhydrides and bis-(α-phenylethylidene)succinic anhydrides to yield 1,2-dihydro naphthalene-2,3-dicarboxylic anhydride derivatives are reported. With the exception of the first, these succinic anhydrides undergo competing but reversible sigmatropic rearrangements to yield penta- and hexa-1,3-diene-3,4 dicarboxylic anhydride derivatives.