Double Kabachnik-Fields condensations

Double Kabachnik-Fields condensations were also elaborated applying two equivalents of the formaldehyde and the >P(0)H species to one equivalent of the primary amine (Scheme 21) [75-77]. 

Furthermore, the same group accomplished the double Kabachnik-Fields condensation reaction using two equivalents of formaldehyde and the >P(0)H species to one equivalent of the primary amine in the synthesis in good yields of a series of bis(phosphonomethyl)amines and related derivatives (64), following a MW-assisted solvent-less procedure (Scheme 30). The investigators then extended the double Kabachnik-Fields reaction to the synthesis of bis(phosphinoxidomethyl)amines (65), and herein the use of acetonitrile as solvent was required (Scheme 31). The bis(phosphinoylmethyl)amines (65) are useful precursors of bidentate... 

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