New Phosphono Substituted 3- and 5-Membered Rings Starting from 3(2-Thienyl)acrylonitriles and α-Phosphoryl Carbanions

A series of phosphono substituted 3- and 5-membered rings were synthesized using the Horner–Wittig reagents 2a–c on 3(2-thienyl)acrylonitriles 1a,b in the presence of different bases. All products are produced according to a sequence that involves an initial Michael reaction between 2 and the exocyclic ethylene linkage of 1a or 1b.