2,3,4-Triphenyl-3-azabicyclo[3.2.0]hepta-1,4-diene - Facile ring-opening by electrophiles and novel reactions with dimethyl acetylenedicarboxylate

Article abstract of DOI:10.1002/ejoc.200400433

A 3-azabicyclo[3.2.0]hepta-1,4-diene with no substituent in the cyclobutene moiety has been prepared for the first time; it undergoes extremely facile electrophilic attack at the β-position to give the ring-opened product, probably by a retro-Friedel-Crafts process. The title compound also undergoes a novel reaction with dimethyl acetylenedicarboxylate to afford the azepine. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.