Process for preparing cyclic phosphines

A process for the preparation of a cyclic phosphine from the corresponding primary phosphine and a bifunctional alkylating agent, wherein alkylation, and displacement of each functional group, occurs in the presence of a strong base, which comprises adding the strong base, in an amount sufficient for cyclisation, to a preformed mixture or reaction product of the primary phosphine and the bifunctional alkylating agent, wherein the cyclic phosphine is of formula (3), the primary phosphine is of formula (4) and the bifunctional alkylating agent is of formula (5)

• wherein m and n are positive integers, the groups R1, R2 and R3 are each any non-interfering radical, wherein R1 and R2 are independently H, alkyl cycloalkyl aryl, aralkyl or alkaryl, provided that both are not H, and R3 is aryl, alkyl, cycloalkyl, aralkyl, alkaryl or an organometallic residue, and wherein X and X1 are each nucleofugal leaving groups, optionally linked to form a ring.