0 . I . KO LODIAZHN YI , I . V . SHEVTCHENKO , V . P . KUKHAR ' Institute of Organic Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev-252094, USSR ... Abstract Synthesis and properties of new phospha- alkenes having different functional substituents at phosphorus and carbon atoms are discussed. ... New phosphaalkenes (type I and 11) containing alkylthio- and fluorenilidene groups at carbon atom of the P=C bond were obtained in ...