Photochemical desulfurization of L-cysteine derivatives

Thiol groups can be reductively eliminated at room temperature by a photochemical method which make:; use of triethylboron, triethylphosphite and visible light. Thus, after treating L-Cys 1a, D-Pen 1b, L-Cys-OMe 1c and glutathione (gamma-L-Glu-L-Cys-Gly) 3, the corresponding desulfurized compounds L-Ala 2a, D-Val 2b, L-Ala-OMe 2e and gamma-L-Glu-L-Ala-Gly 4, respectively, are prepared in high yields and with retention of configuration. (C) 1998 Elsevier Science Ltd. All rights reserved.