Ammonium acid formate phosphite

The original Kabachnik-Fields procedure employing ammonia as the amine component used ammonia in ethanol and the reactions were performed in sealed vessels at circa 100°C.90,123 This method avoids such conditions by using ammonium acetate as the source of ammonia, and it is also thought to act as an acid catalyst for imine formation other ammonium salts were unsatisfactory. Addition of water to produce a homogeneous reaction mixture resulted in diethyl 1-hydroxy-1-benzylphosphonate formation (i.e. from direct attack of diethyl phosphite 25 on benzaldehye, a common side reaction in the Kabachnik-Fields reaction). The yields of this reaction are serviceable, and better for aromatic than aliphatic aldehydes. The product 58 may be further purified by crystallization as the hydrochloride salt by treatment of 58 with hydrogen chloride in ethanol/diethyl ether.122... 

Tanaka et al. [8] proposed a very elegant strategy based on porphyrins peripherally modified with dibenzol[24]crown-8 and a secondary ammonium ion, able to form rotaxanes. In fact, the interaction of a porphyrin with a phthalocyanine lead to the formation of a stable jt-stacked pseudo-rotaxane after end-capping the ammonium chains by reaction with Staudinger-phosphite in chloroform, followed by metallation with Cu(II). In acidic media, the ammine and phosphoramide groups are protonated generating a tetracationic species that can form ion-pairs with the tetraanionic [Cu-TSPP] species [9]. 

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