Convenient Methods for the Synthesis of a Library of Hemilabile Phosphines

A series of novel functionalized phosphines of hemilabile character, R 2P(CH2)nZ, have been prepared from diarylphosphines using several synthetic methodologies. The synthetic methods include the alkylation of lithium diarylphosphide or (diarylphosphino) borane adducts with functionalized halogenoalkanes, X(CH2)nZ, and the photochemical hydrophosphination of suitable functionalized allyl or vinyl derivatives, H2C=CHZ or H2C=CHCH2Z, using white light. A range of R2PH (R = Bn, 4-MeOC6H4, 4-MeC6H4, 2-MeC6H4, Ph, 4-F 3CC6H4) has been used in order to tune the electronic density on the phosphorus donor atom. The coordination ability of the hemilabile fragment was modified by selection of the donor group (Z = OMe, OEt, OBu, NMe2) or the length of the flexible carbon chain (n = 2, 3). Hemilabile fluorinated allylphosphines, R2PCH2CH=CH 2 (R = 4-FC6H4, C6F5), have been prepared from diarylchlorophosphines and allylmagnesium bromide.