Highly Diastereoselective Synthesis of Cyclic α‐Aminophosphonic and α‐Aminophosphinic Acids from Glycyl‐l‐Proline 2,5‐Diketopiperazine

Abstract

This paper describes the first diastereoselective synthesis of cyclic α-aminophosphonic and α-amino phosphonic acids from glycyl-L-proline 2,5-diketopiperazine (S)-6 prepared according to the usual peptide coupling procedures. The highlights of this contribution is the chemoselective reduction of the carbamate-imide activated carbonyl group in the N-Boc 2,5diketopiperazine (S)-11 to generate the unstable hemiaminals (1R,8aS)-12 and (1S,8aS)-13, followed by the highly diastereo- [a]

Exploring Sources, Biological Functions, and Potential Applications of the Ubiquitous Marine Cyclic Dipeptide: A Concise Review of Cyclic Glycine-Proline

“…After removing the N -Boc protecting group, the intermediate undergoes intramolecular cyclisation upon heating, producing a cyclic dipeptide at a 64% yield ( Figure 3 : Route A). Another method involves a C-N bond-forming sequence using N -Boc- L -proline 11 , followed by the steps listed above to produce a cyclic dipeptide at a 71% yield ( Figure 3 : Route B) [ 16 , 54 , 55 ]. A third approach includes acylating N -Boc- L -proline and coupling the resulting product with glycine methyl ester hydrochloride; refluxing with water produces a cyclic dipeptide at a yield of 87% ( Figure 3 : Route C) [ 56 ].…”

Synthesis of Phosphinopeptides and Phosphinodepsipeptides

“…Acid hydrolysis of the phosphinate functionalities with simultaneous cleavage of the tert ‐butyl carbamate protecting group led to cyclic α‐aminophosphinic acid (Scheme 13). It was considered as cyclic phosphinodipeptide analogue with C ‐terminal β‐aminoalkylphosphinic acid [44] …”

“…It was considered as cyclic phosphinodipeptide analogue with Cterminal β-aminoalkylphosphinic acid. [44]…”

Stereocontrolled Synthesis of Phosphoproline Analogues Containing a trans-Fused Octahydroindole Bicyclic System

“…Considering the high biological potential of the trans -fused phosphonic analogue of Oic, which invites comprehensive studies, in connection with our current research interest in the synthesis of conformationally constrained α-aminophosphonic acids, we present herein the first stereocontrolled synthesis of enantiomerically pure (2 R ,3a R ,7a S )- and (2 S ,3a S ,7a R )-octahydroindole-2-phosphonic acid 2 (Oic P ) (Figure ). The key synthetic steps involve the ruthenium tetroxide-mediated oxidation of enantiomerically pure diethyl ( R )- and ( S )-phosphoprolinate and Grubb’s ring-closing metathesis of a suitable trans -4,5-diallylated intermediate obtained from diethyl ( R )- and ( S )-phosphopyroglutamate.…”