Cross metathesis for the synthesis of novel C-sialosides
摘要:
Cross metathesis of both anomers of C-allyl sialoside (3 alpha/3 beta) with styrene catalyzed by the second generation Grubbs or Hoveyda-Grubbs catalysts gave the corresponding aryl derivatives (4 alpha/4 beta) in virtually quantitative yields. The products were hydrogenated to model compounds 5 alpha/5 beta. Similarly, reaction of the alpha-anomer 3 alpha with galactose derivative 8 gave the olefin-linked disaccharide mimetic 9. Following hydrogenation and deprotection, the ethylene-bridged Neu5Ac alpha(2 -> 6)Gal analogue 11 could be obtained. (c) 2008 Elsevier Ltd. All rights reserved.