Wasserlösliche Phosphane, IV. Tertiäre Alkylphosphane mit Ammoniumgruppen in den Seitenketten – Amphiphile mit basischen P‐Atomen

Abstract

Water‐Soluble Phosphanes, IV. – Tertiary Alkylphosphanes with Ammonium Groups in the Side Chains — Amphiphiles with Basic P‐AtomsBy stepwise aminoalkylation of PH3 with Me2N(CH2)2Cl in the superbasic medium DMSO/KOH the secondary phosphane [Me2N(CH2)2]2PH (2) is obtained in good yields. Metallation of 2 with n‐BuLi and subsequent reaction with Me2N(CH2)2]2Cl affords the basic tertiary phosphane [Me2N(CH2)2]2]3P (3), which on protonation with Ph3P · HBr in CH2Cl2 gives {[HNMe2 − (CH2)2]3P}3+ 3 Br− (4a) with an extremely high solubility in water. By oxidation of 3 with H2O2 and N‐quaternisation with Me3O+ BF the cationic phosphane oxide {[Me3N(CH2)2]3PO}3+ 3 BF (5a) is formed, which could, however, not be reduced with SiHCl3 or Si2Cl6/NEt3 to the corresponding tricationic phosphane. Tertiary cationic phosphanes of type [RMe2N(CH2)2P(Oct)2]+ X− (8a, 8b, R = Me, C8H17; X = Br, I) are accessible by free radical addition of 1‐octene to 7b and 7d. Addition of formaldehyde to 7a gives the hydroxymethyl phosphane 10a. By methylation of [RMe2N(CH2)2PH2]+I− (7d and 7e, R = CnH2n+1, n = 8, 12) with Mel under controlled condition and subsequent deprotonation of the phosphonium salts 12b and 12c the cationic tertiary phosphanes 13a and 13b with long alkyl side chains may be obtained in good yields.