Photochemical desulfurization of thiols and disulfides

A visible light-induced desulfurization process for thiols and disulfides u sing triethylphosphite and triethylborane is reported. The reaction can be effected on a range of organic molecules having either primary, secondary o r tertiary thiol groups and disulfides without the need of protecting group s. Thus, after treating L-cystine 7, L-cystine dimethylester 8, thioctic am ide 9 and glutathione disulfide 10, first with tributylphosphine, later wit h triethylborane/triethylphosphite under irradiation in a one-pot reaction, the corresponding desulfurized compounds L-Ala, L-Ala, 1-octanamide and ga mma-L-Glu-L-Ala-Gly, respectively, are prepared in high yields with retenti on of configuration. (C) 1999 Elsevier Science Ltd. All rights reserved.