ABSTRACT: A description of the preparation of diethyl 3-bromopropene phosphonate, 1 , is reported. The use of this reagent as an acetone equivalent for the annulation of five-membered rings is described. ... One of the simplest strategies for annulation of a cyclopentenone ring to a carbon skeleton involves alkylation of a ketone with an acetonyl equivalent, unmasking the new appendage into a carbonyl species and ... Diethyl 3-bromopropene phosphonate, 1, ...
