Dk. Dikshit et al., SELF REPRODUCTION OF CHIRALITY IN PYROGLUTAMATES - REACTIONS AT ALPHA-POSITION WITH ELECTROPHILES, Tetrahedron letters, 36(34), 1995, pp. 6131-6134
Condensation of pyroglutamic acid with trimethylacetaldehyde gave a bi
cyclic derivative which on deprotonation with LiHMDS and reaction with
electrophiles gives chiral cl-substituted pyroglutamate derivatives.