γ-Alkylsulfide phosphonates through the thia-Michael strategy

The formation of γ-alkylsulfide phosphonates is described from allylphosphonates under mild conditions using thiols through the thia-Michael strategy. A series of new phosphonates, bisphosphonates were cleanly prepared in high yields. The methodology developed allowed further preparing γ-alkylsulfide phosphonates bearing valuable esters groups in β and δ positions with respect to the phosphonate moiety.