We wish to report a convenient and versatile new synthetic route to a-lipoic acids. The alkylation of sodium disulfide to form the l,”-dithiolane ring has been described. I6 We have treated G, S-dichlorooctanoic acid and its esters8 with solutions of sodium disulfide to give a- lipoic acid and its esters, re~ pectively.~~ The sequence of reactions represented below permits the preparation of DL-a-lipoic acid,(+)-a-lipoic acid and DL-a-lipOiC acid-S235.
