oxidative decarboxylation of cyclic alpha-amino acids having urethane-type N-protecting groups with lead tetraacetate [Pb(OAc)4] gave 2-hydroxy derivatives, which were transformed into the corresponding alpha-aminophosphonic acid esters by treatment of trialkyl phosphites in the presence of Lewis acids. Deprotection and ester cleavage of the products in the usual manner afforded cyclic alpha-aminophosphonic
A Straightforward Synthesis of Six‐Membered‐Ring Heterocyclic α‐Aminophosphonic Acids from
<i>N</i>
‐Acyliminium Ions
作者:Rubén Oswaldo Argüello‐Velasco、Grecia Katherine Sánchez‐Muñoz、José Luis Viveros‐Ceballos、Mario Ordóñez、Pawel Kafarski
DOI:10.1002/jhet.3593
日期:2019.7
A convenient synthesis of phosphonicanalogues of pipecolic acid and its heterocyclic analogues is reported. The major step of the elaborated procedure is the introduction of the phosphonate group into the skeleton of the appropriate cyclic amide through N‐acyliminium ions. The former ones were obtained by preparation of the hemiaminals or their methyl ethers from the N‐protected cyclic amides. Finally