SYNTHESIS OF BIS(PHOSPHINOMETHYL)AMINES VIA BIS(HYDROXYMETHYL)PHOSPHONIUM SALTS - ISOLATION OF 9,9-BIS(HYDROXYMETHYL)-9-PHOSPHONIABICYCLO[3.3.1]NONANE HYDROGENSULFATE AND CHLORIDE SALTS, AND THE CRYSTAL-STRUCTURES OF [PPH2(CH2OH)2]+CL- AND [(C6H11)2PCH2]2- NCHMEPH

Phosphines of the type PR2H reacted readily with formaldehyde in the presence of acid to afford high yields of bis(hydroxymethyl)phosphonium salts [PPh2(CH2OH)2]+X-, [P(C6H11)2(CH2OH)2]+X-, [CH2CH2CH2CH2CHP(CH2OH)2CHCH2CH2]+X-, and [CH2CH2CH2CHP(CH2OH)2CHCH2CH2CH2]+X-(X=Cl or HSO4). Treatment of the mixed isomers of the bicyclononane phosphonium cation [P(C8H14)(CH2OH)2]+ in boiling H2SO4 gave a [3.3.1] isomer, the [4.2.1] isomer undergoing decomposition. A single-crystal X-ray diffraction study has been carried out on the phosphonium salt [PPh2(CH2OH)2]+Cl-. The geometry around phosphorus is essentially tetrahedral, and there is hydrogen bonding between the hydroxyl groups and the chloride anion. Treatment of these phosphonium salts with triethylamine and a primary or secondary amine afforded aminomethylphosphines (R2PCH2)2NR' (R = Ph, R'= CHMePh, CHMeCO2Me, CHMeCO2Et, CHCH2CHCH2CH2CMeCMe2, CH2CH2OH or CH2CH=CH2; R = C6H11, R'= CHMePh or CHMeCO2H; R2 = C8H14, R' = CHMePh) or C8H14PCH2NEt2 in good yields. A single-crystal X-ray diffraction study has been carried out on [(C6H11)2PCH2]2NCHMePh.