A study on the kabachnik‐‐fields reaction of benzaldehyde, cyclohexylamine, and dialkyl phosphites

Abstract

The Kabachnik–Fields reaction of benzaldehyde, cyclohexylamine, and dimethyl phosphite carried out at 80°C in acetonitrile takes place via an imine (PhCNcHex) intermediate, as the monitoring by in situ Fourier transform IR spectroscopy suggested. The corresponding α‐hydroxyphosphonate was also formed in a quantity of 13% that was not converted to α‐aminophosphonate under the conditions applied. The outcome was similar to the Kabachnik–Fields reaction with diethyl phosphite as the P‐component. Molecular modeling and subsequent DFT calculations carried out under solventless conditions supported the experimental results and indicated the formation of a high number of ideally positioned H bonds as the key determinant for the conformation of the starting, intermediate, and product states. The relative energies of the possible intermediates were in accord with the observation that the formation of the α‐hydroxyphosphonate is a “dead‐end” route. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:171–178, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20767

N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic activity of the related bidentate chelate platinum complexes in hydroformylation

“…One of the authors of this article with co-workers could prove the intermediacy of the imine intermediate in a few cases studied utilizing the method of in situ Fourier Transform Infrared spectroscopy [13,14].…”

Convenient approach to synthesize tertiary α-hydroxy cyclic phosphonates catalyzed by potassium carbonate under solvent-free conditions

“…18 There are some methods for the synthesis of hydroxyphosphonates under solvent-free conditions. [19][20][21][22] In this study, we describe the solvent-free synthesis of tertiary α-hydroxy cyclic phosphonates by the hydrophosphonylation of ketones (Scheme 1).…”

The Synthesis of N,N‐Bis(dialkoxyphosphinoylmethyl)‐ and N,N‐Bis(diphenylphosphinoylmethyl)glycine Esters by the Microwave‐Assisted Double Kabachnik–Fields Reaction

“…The mechanism of reaction also generated a considerable interest, in whether imines (Schiff bases) or α‐hydroxyphosphonates are the intermediates of the Kabachnik–Fields reaction . The way of accomplishment has also been in focus.…”