Easy access to alkylphosphine boranes starting from unactivated alkenes

An efficient and simple method for the preparation of P-alkyl substituted phosphines is described. The desired phosphines are produced in good yields by hydrophosphination of unactivated alkenes using secondary phosphine boranes under both conventional and microwave conditions. No catalyst is required, the reaction simply occurs at room temperature or under a slight thermal activation (60 deg C in oil bath or under microwave irradiation). This methodology provides a means for the preparation of a structurally diverse set of tertiary phosphines from simple low-cost commercially available alkenes.