Microwave-assisted solventless single and double addition of HP(O)Ph2 to alkynes

Abstract Microwave radiation has been used to promote the addition of diphenylphosphine oxide to alkynes. The addition reactions were carried out using homogeneous and polymer-supported Group 9 catalysts such as (PPh 3 ) 3 RhCl, [Rh(cod)Cl] 2 , and Rh/supported triphenyl phosphine. Solventless reactions involving terminal alkynes were extremely rapid, and high yields of the alkenylphosphine oxides were obtained in 2 min using microwave radiation. The hydrophosphinylation of internal alkynes such as 4-octyne was also rapid (20 min). For comparison, addition reactions were carried out using conventional heating with the solid supported catalysts. The supported catalyst prepared from oligo(vinyl diphenylphosphine- co -vinyl diphenylphosphine oxide- co -vinyl chloride) was reused seven times to promote the addition of HP(O)Ph 2 to 1-heptyne with >90% conversion obtained in each case.