Formal synthesis of valienamine using ring-closing metathesis

1R,2S,3S,4R)-2,3,4-Tri-O-benzyl-5-(benzyloxymethyl)-cyclohex-5-ene-l,2,3,4-tetrol, a precursor of the cc-glucosidase inhibitor, valienamine, was synthesised in eight steps from tetrabenzyl glucose. The key steps were the selective protection of an open-chain diol, and the formation of the cyclohexene ring by ring-closing metathesis with the trisubstituted olefin of valienamine correctly in place. (c) 2005 Elsevier Ltd. All rights reserved.