The first synthesis of a pair of (R)- and (S)-piperidazine-3-phosphonic acids was performed via a one-pot process of hetero Diels–Alder reaction and Lewis acid-catalyzed phosphonylation. The absolute configuration of the target compounds was established by a novel transformation into known (R)- and (S)-pyrrolidine-2-phosphonic acids.
A simple and convenient method has been developed for the preparation of (R)- and (S)-pyrrolidine-2-phosphonic acids. The thermal reaction of proline with diethyl phosphite in the presence of benzaldehyde gave an N-benzyl derivative of diethyl pyrrolidine-2-phosphonate, which was transformed into two diastereomeric amides by sequential debenzylation and acylation with (+)-dibenzoyl-l-tartaric anhydride
Enzymatic and chromatographic resolution procedures applied to the synthesis of the phosphoproline enantiomers
作者:Alicia Arizpe、María Rodríguez-Mata、Francisco J. Sayago、María J. Pueyo、Vicente Gotor、Ana I. Jiménez、Vicente Gotor-Fernández、Carlos Cativiela
DOI:10.1016/j.tetasy.2015.10.016
日期:2015.12
The preparation of enantiomerically pure pyrrolidine-2-phosphonic acid (phosphoproline, Pro(P)) has been addressed through the synthesis of suitable racemates and subsequent resolution by independent enzyme-catalyzed and chiral HPLC methods. First, racemic phosphoproline derivatives bearing the necessary protecting groups have been synthesized in excellent global yields starting from inexpensive materials. Preparative HPLC resolution of the N-Cbz-protected aminophosphonate on a cellulose-based column allowed the isolation of enantiomerically pure enantiomers on a gram scale. Enzyme-catalyzed alkoxycarbonylation of the aminophosphonate was studied using different lipases, solvents, and carbonates. Candida antarctica lipase type A (CAL-A) provided the highest enantioselectivity when combined with benzyl 3-methoxyphenyl carbonate. (c) 2015 Elsevier Ltd. All rights reserved.