Phospha-Mannich reactions of RPH₂, R₂PH, and R₃P

Phosphorus-based Mannich-type reactions (phospha-Mannich reactions) of primary or secondary phosphines with carbonyl compounds and amines (R2NH, RNH2, NH3) provide a powerful synthetic tool in the worldwide search for future ligands. The variety available allows designing fine-tuning water-soluble, chiral, macrocyclic, pincer, tripodal, photoactive, etc., phosphine ligands P–C–N linkage(s) (P,N-acetals). Aminized supports amine-terminated dendrimers can easily be phosphine-functionalized by phospha-Mannich reactions, used reusable heterogeneous catalysts. If CH2O is as C-component, its stable adducts phosphines, that is, RP(CH2OH)2 R2PCH2OH, are often syntheses P,N-acetals they less toxic non-pyrophoric analogs whereas other usually converted into imines iminium salts. In tertiary form P+–C–N linkage (P+,N-acetals) broken bases, realizing imine, cations, imine/iminium donors organic syntheses.