N. Langlois et A. Rojas, SYNTHESIS OF (2S,4S) 2-CARBOXY-4-PYRROLIDINE ACETIC-ACID, A CONFORMATIONALLY CONSTRAINED 2-AMINO ADIPIC ACID ANALOG, Tetrahedron letters, 34(15), 1993, pp. 2477-2480
(2S,4S) 2-carboxy-4-pyrrolidine acetic acid was synthesized from (S) p
yroglutamic acid in 26% overall yield by a regiospecific deprotonation
of the N-methoxycarbonyl benzylester 4.