Novel synthesis of 3-chloromethylidene-2-ethoxy-1,2λ5-oxaphospholan-2-ones catalysed by palladium(II)
Abstract
2-Ethoxy-3-methylidene-1,2λ5-oxaphospholan-2-one rings have been constructed by Pd(OAc)2–LiCl catalysed cyclization of 4-chlorobut-2-enyl ethyl alkynylphosphonate. A mechanism involving trans or cis halogenopalladation, followed by intramolecular insertion of a carbon–carbon double bond into a carbon–palladium bond and subsequent dehalogenopalladation, is briefly discussed.