Heteroarylmethylenephosphorus
ylides underwent Michael addition
with alkynediones and alkynediesters, followed by intramolecular cyclization
and elimination of triphenylphosphine oxide to afford 1,2-diaroylbenzenes
and 1,2-alkoxycarbonylcarbo- and heterocycles. The analogous
(4 + 2) cycloaddition led to the formation of 2,3-diaroylquinolines.