Thiomaleic anhydride: a convenient building block for the synthesis of alpha-substituted gamma- and delta-lactones through free-radical addition, nucleophilic ring opening, and subsequent thiocarboxylate manipulation.

ABSTRACT: Iodoalkyl tert-butyl carbonates and carbamates undergo clean free-radical addition to thiomaleic anhydride to give substituted thiosuccinic anhydrides in high yield on treatment with tris(trimethylsilyl)silane and a radical initiator. After removal of the tert-butyloxycarbonyl group, cyclization then affords lactones or lactams substituted in the alpha-position by a thiocarboxylic acid residue. This group is converted to amides through reaction with electron-deficient sulfonamides or to aldehydes and/or ketones by the reaction of derived thioesters with either thiophenol, an electron-deficient allyl phenyl sulfide, or phenylboronic acid.

SUBMITTER: Crich D 

PROVIDER: S-EPMC2778001 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature