Reactions of p-Toluenesulfonates with Lithium Triethylborohydride. Visible and Hidden Rearrangements

Article abstract of DOI:10.1021/jo00350a044

The reaction of methyl 6-deoxy-2,3-di-O-p-tolylsulfonyl-α-D-galactopyranoside (4) with lithium triethylborohydride (LTBH) gives three primary products, all of which result from rearrangement.One of these, methyl 5-deoxy-3-C-(hydroxymethyl)-2-O-p-tolylsulfonyl-α-D-xylofuranoside (7), arises from ring contraction while the other two, methyl 3,6-dideoxy-2-O-p-tolylsulfonyl-α-D-xylo- (5) and -ribo-hexopyranosides (9), result from hydride migration and reduction of the resulting ketone, methyl 3,6-dideoxy-2-O-p-tolylsulfonyl-α-D-erythro-hexopyranosid-4-ulose (8).Photolysis of compounds 4, 5, and 9 removes the tosyl groups.