Kabachnik–Fields reaction

The Kabachnik-Fields reaction is a multi component reaction in which an aldehyde ( R2 = H, R3 = H or Organylgruppe ), an amine (R1 = H, Organylgruppe ), and a phosphonic acid ( (R4 = H, Organylgruppe ) (R5 = H, Organylgruppe ) ) are reacted to give a α - aminophosphonate. The reaction was discovered by Martin and Ellis K. Fields Izrailevich Kabachnik independently in 1952.

Mechanism

In the first step, the amine attacks the aldehyde on the carbonyl carbon atom. The result is a zwitterion, which reacts by rearrangement of a hydrogen atom ( tautomerism ) and subsequent elimination of water to the imine. In the next step, the phosphonic acid derivative is added to the imine. After a further transfer of a hydrogen atom is, ultimately, an α - amino phosphonate.