Phospha-Michael-Type Reactions between 1,2-Diaza-1,3-dienes and Bidentate Nucleophiles: Formation of New Mono- and Diylides and their Elaboration to Heterocycles

Phospha-Michael additions of a series of methylene-bridged phosphorus bidentate nucleophiles to 1,2-diaza-1,3-dienes gave monoadducts and bisadducts in high yields under mild conditions. In particular, a series of new ylides and symmetrical diylides have been obtained from bis(diphenyl)phosphanes. The use of diphenylphosphanylamino derivatives gave, through phospha-Michael addition, ylide intermediates that underwent spontaneous intramolecular attack by the amino group belonging to the Michael donor reagent moiety, thus giving access to new heterocycles.