Solid-phase synthesis of beta-mannosides.
The linkage of S-phenyl 2,3-di-O-benzyl-alpha-D-thiomannopyranoside to a cross-linked polystyrene support in the form of its 4,6-O-polystyrylborinate ester is described. The activation of this polymer-supported mannosyl donor is achieved at -60 degrees C in dichloromethane in the presence of 2,4,6-tri-tert-butylpyrimidine with the combination 1-benzenesulfinyl piperidine and trifluoromethanesulfonic anhydride. Addition of the donor alcohol at -60 degrees C followed by warming to room temperature and subsequent cleavage from the resin by gentle heating in aqueous acetone yields anomerically pure 2,3-di-O-benzyl-beta-D-mannopyranosides in excellent yield. Successful, diastereoselective coupling is demonstrated with a range of primary, secondary, and tertiary glycosyl acceptors, including typical carbohydrates and threonine derivatives.
Crich
David
D
Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA. dcrich@uic.edu
Smith
Mark
M
D002236:Carbohydrate Conformation; D008358:Mannose / Q000138:chemical synthesis; D008362:Mannosides / Q000138:chemical synthesis*; D011137:Polystyrenes / Q000737:chemistry
D008362:Mannosides; D011137:Polystyrenes; D008358:Mannose