Heterocumulenes: Reaction of C_3O_2 Ketenylidenetriphenylphosphorane; Synthesis and Structure of a Spirobis(cyclobutanedione)

摘要

Acylketenes (alpha-oxoketenes) are subject to increasing interest and are used extensively as synthetic building blocks for a large number of interesting compounds. Recently we reported that the simplest stable bis(ketene), carbon suboxide (1). reactswith stabilized phosphonium and arsonium ylides141 bearing a hydrogen atom on the ylidic carbon atom. Depending on the ylide, bis(ylidic) malonil derivatives or zwitterionic pyrone derivatives are formed, but Wittig-type reactions were never observed.