Synthese primärer und sekundärer Phosphane durch selektive Alkylierung von PH3 unter Phasentransferbedingungen / Synthesis of Primary and Secondary Phosphines by Selective Alkylation of PH3 under Phase Transfer Conditions

Abstract

Primary phosphines, RPH₂, may be synthesized selectively by alkylation of phosphine, PH₃, with alkyl halides RX (R = Me, Et, n-Bu, 2-Bu, C₁₆H₃₃, CH₂=CH–CH₂, Ph–CH₂, 2-Py–CH₂–CH₂; X = Cl, Br) and concentrated aqueous KOH as auxilliary base in dimethylsulfoxide as a solvent or in two phase systems employing phase transfer catalysts. Under more rigorous conditions secondary phosphines R₂PH (R = Me, n-Bu, CH₂=CH–CH₂) are also accessible in good yields. Using 1,3-dibromo(chloro)-propane or -butane diprimary phosphines H₂P–(CH₂)₂–CHR–PH₂ (R = H, Me) are obtained, while 1,4-dibromopentane in a high yield cyclization reaction leads to 2-methylphospholane (12) with a chiral C-atom in a-position.