4,4-Disubstituted 1,2-dithiolanes as simple models for enzyme-bound lipoic acid

Two substituents on C-4 drastically reduce the tendency of 1,2-dithiolane to polymerize, whereas they do not significantly alter the reactivity of the remote disulfide; the dithiolanes 1a–e show high reactivity towards the carbon nucleophile EtMgBr as expected for the enzyme-bound lipoic acid.