Journal of the American Chemical Society, Vol.122, No.37, 8869-8872, 2000
A novel beta-directing fructofuranosyl donor concept. Stereospecific synthesis of sucrose
A new concept for the construction of beta-D-fructofuranosides based on the idea of locking the anomeric CH2OH group to the alpha-side through an internal bridge to the 4-hydroxyl group is presented. Thioglycoside fructose donors containing an internal 1,4-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl) (TIPS) acetal bridge have been constructed and used in glycosylations with dimethyl(thiomethyl)sulfonium triflate (DMTST) as promoter. The couplings were stereospecific to give beta-D-fructofuranosyl disaccharides in high yields. Using this approach, sucrose has been synthesized stereospecifically in 80% yield.