Preparation and structural determination of methyl 3-C-p-tolylsulfonyl-2-C-p-tolylthio-β-d-glucopyanoside derivatives and their 5a-carba-dl-analogs having non-chair conformation in solutions

Preparation of 2-deoxy-2-C-p-tolylsulfonyl-β-d-glucopyranosyl p-tolyl sulfones having non-chair conformation and their elimination reactions

“…3 A sulfonyl group at C-1 behaves as a leaving group; 4 therefore, we have synthesized 2-C-p-tolylsulfonyl-b-D-glucopyranosyl p-tolyl sulfone, expecting that such a compound exceptionally occupies a non-chair conformation, because we found that methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-C-di-p-tolylsulfonyl-b-D-glucopyranoside (1) adopts a non-chair conformation in solution. 5 The intended ditosyl derivative 5 was prepared by addition of p-tolylsulfenyl chloride to tri-O-acetyl-D-glucal (2), 6 followed by addition of sodium p-tolylthiolate in methanol, and then oxidation with m-chloroperbenzoic acid (Scheme 1). Compound 5, as expected, occupies a non-chair conformation as judged from the coupling constants, J 1,2 3.3, J 2,3 5.4, J 3,4 8.6, and J 4,5 10.3 Hz.…”