Synthesis and Molecular Structure of β‐Phosphinoyl Carboxamides: An Unexpected Case of Chiral Discrimination of Hydrogen‐Bonded Dimers in the Solid State

Abstract

A series of N,P,P-trisubstituted aminophosphanes react with diphenylcyclopropenone to afford an easily separable mixture of two diastereomeric alpha,beta-diphenyl-beta-phosphinoyl carboxamides in good yields. X-ray crystal structures reveal that these compounds associate into dimers, formed from two enantiomeric units linked by two bifurcated hydrogen bonds, whereby the oxygen atom of the phosphoryl group acts as a dual acceptor for the vicinal NH and CH of a carbonyl group of a neighbouring molecule. Studies on the interconversion between diastereomeric phosphinoyl carboxamides in basic solution show that the thermodynamically most stable isomer depends on the nature of the substituent at the nitrogen atom. Simple computational calculations explain this phenomenon.

A Bioorthogonal Ligation of Cyclopropenones Mediated by Triarylphosphines

“…Ketene ylides can be long-lived and even isolated under ambient, moisture-free conditions . However, these moieties are susceptible to rapid reaction with both oxygen and amine nucleophiles. ,− We hypothesized that intermediate 1 could be formed under aqueous conditions and competitively trapped with strong nucleophiles (e.g., amines) even in the presence of water. The selectivity could be further enhanced by tethering the desired nucleophile to the phosphine core or using an excess of an exogenously delivered probe.…”

Phosphine‐Promoted Cyclization of Dicyclopropenones

“…In 2006, Wender13c reported rhodium(I)‐catalyzed [3+2] cycloaddition reactions of cyclopropenones and alkynes to afford cyclopentadienones. And López‐Leonardo et al 13e. focused on the reaction of diphenylcyclopropenone with a series of N ‐alkyl‐ and N ‐arylamino‐ P , P ‐diphenylphosphanes to produce the ketene intermediates and in turn to afford β‐phosphinoyl carboxamides under the standard conditions 14.…”

Lanthanide Silylamide-Catalyzed Synthesis of Pyrano[2,3-b]indol-2-ones

“…They have been found to be efficient catalysts for a series of valuable transformations . On the other hand, as amphiphilic microcyclic molecules with large ring strain, cyclopropenones have often been used as building blocks for the construction of larger molecules . Accordingly, in the course of our development of efficient strategies for building cyclic compounds, we conceived the idea of establishing a method for the synthesis of pyrano­[2,3- b ]­indol-2-ones using a lanthanide silylamide as the catalyst and cyclopropenone as the starting material.…”