An Expansion of the Role of the Corey - Link Reaction for the Synthesis of α-Substituted Carboxylic Acid Esters

Abstract

The treatment of 1,2:5,6-di-O-isopropylidene-α-d-ribo-hexos-3-ulose with chloroform under basic conditions has yielded the normal 3-C-trichloromethyl-α-d-allofuranose derivative. Under the conditions of the modified Corey–Link reaction but with a nucleophile different from the usual azide, a range of α-substituted carboxylic acid esters (and one amide) has been obtained. A similar addition of bromoform to the ulose has formed the α-bromo methyl ester. Two attempts at forming an ‘inositol α-amino acid’ from a polyhydroxylated cyclohexanone failed. Single-crystal X-ray structure determinations are reported for (3S)-1,2:5,6-di-O-isopropylidene-3-C-methoxycarbonyl-3-S-phenyl-3-thio-α-d-ribo-hexose, (3S)-1,2:5,6-di-O-isopropylidene-3-S-phenyl-3-C-(phenylthio)carbonyl-3-thio-α-d-ribo-hexose, 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methoxycarbonyl-α-d-erythro-hex-3-enofuranose, 4,6-di-O-benzyl-2-C-trichloromethyl-scyllo-inositol 1,3,5-orthoformate, 2,2'-anhydro-4,6-di-O-benzyl-2-C-dichlorohydroxymethyl-scyllo-inositol 1,3,5-orthoformate, 1,3,4,5,6-penta-O-benzyl-2-C-trichloromethyl-myo-inositol, and 2-amino-1,3,4,5,6-penta-O-benzyl-2-C-cyano-2-deoxy-myo-inositol.