1‐Aminovinylphosphonate Esters as Substrates for the Diels‐Alder Reaction: First Synthetic and Theoretical Study

Abstract

The Diels‐Alder reaction of 1‐aminovinylphosphonate esters has been studied for the first time as a suitable procedure leading to quaternary carbocyclic α‐aminophosphonates. The reaction is influenced by steric effects at the phosphonate functionality (bulky groups hinder the reaction) and electronic effects at the amino group (electron‐withdrawing substituents increase the reaction rate). The exo/endo ratio is constant, and no influence of the solvent is observed. The experimental results have been rationalized by DFT methods.

Synthesis of β‐Aryl‐α,β‐Dehydroaminophosphonates by Pd‐Catalyzed Fujiwara–Moritani C−C Coupling

“…On the other hand, it relates to the compromise solution that ethyl esters represent for the phosphonate group, since they are more stable than methyl esters [16] without significantly increasing steric bulkiness. The synthesis of 1 has been carried out using methods described in the literature [5a,8a,17] . Toluene 2 a has been used as the arene due to its high boiling point and because it is an excellent NMR probe.…”

“…Samples were introduced in a continuous flow of 0.2 mL/min and nitrogen served both as the nebulizer gas and the dry gas. The starting material diethyl (1‐acetamidovinyl) phosphonate ( 1 ) was prepared following published methods [5a,8a,17] …”

A novel approach for obtaining α,β-diaminophosphonates bearing structurally diverse side chains and their interactions with transition metal ions studied by ITC

“…Alternatively, the substrate 1 and 3 could be synthesized using the different routes. 32,33 The structures of phosphonodehydroalanine 3 and a n.i.product was not isolated from the reaction mixture. Reagent dosages: 1 or 3 (0.5 mmol); piperidine (2.5 mmol), RT.…”