One-pot diastereoselective synthesis of chiral tricyclic L-cysteine and D-penicillamine derivatives: a laboratory experiment

Abstract

A one-pot diastereoselective synthesis of thiazolidine-ring fused systems derived from enantiomerically pure amino acids, L-cysteine or D-penicillamine, and achiral succindialdehyde is described as an experiment to be carried out by upper-division undergraduate students in a laboratory classroom. Reactions were performed under mild conditions, the products were isolated through simple experimental procedures and fully characterized. This study combines organic synthesis, determination of the purity of compounds (TLC analysis and melting point measurements), optical activity measurements as well as structural analysis (interpretation of 1D NMR and 2D NMR spectra). It offers a platform for the discussion of important organic chemistry concepts such as diastereoselectivity, kinetic control vs thermodynamic control and cyclization reactions via nucleophilic addition to imines/iminium cations.