Synthetic method for carbon-carbon and carbon-heteroatom bonds using phosphorus reagents

Abstract

A novel and efficient synthetic method for carbon-sulfur, carbon-carbon and carbon-chlorine bonds using phosphorus reagents was disclosed. 1) Oxidation-reduction condensation between 2-sulfanyl-1,3-benzothiazole (HSBtz) and tertiary alkyl diphenylphosphinites could smoothly be proceeded in the presence of camphor quinone (CPQ) as a new oxidant to furnish the corresponding sulfide in good yields via SN2 displacement. Subsequent removal of the Btz groups of S-alkylated products provided dialkyl sulfides. 2) The combination of alkyl diphenylphosphinites and 2,6-di-tert-butyl-1,4- benzoquinone (DBBQ) was disclosed as a new synthetic route for carbon-carbon bond formation. The DBBQ-induced condensation of primary and secondary alkyl diphenylphosphinites with active methylene compounds such as (phenylsulfonyl) acetonitrile, bis(phenylsulfonyl)methane and dibenzyl malonate proceeded smoothly at room temperature to form the C-alkylated products in moderate to high yields. 3) The chlorination of alcohols utilizing a new combination of triphenylphosphine (PPh3) and trichloroacetamide (Cl3CCONH2) furnished the corresponding alkyl chlorides in high yield under mild conditions within short reaction time. Primary alcohols appear to be the most reactive substrate towards CI3 CCONH 2 /PPh3 yielding exclusively the corresponding chlorides. The general mechanism was believed to occur via SN2 supporting by the evidence of the inversion of configuration of the analogous alkyl chloride.