Multigram scale synthesis of formyl tetra-O-benzyl-beta-D-C-glucopyranoside using benzothiazole as a formyl group equivalent

The addition of 2-lithiobenzothiazole to D-gluconolactone followed by deoxygenation of the resulting ketose affords a mixture of benzothiazolyl alpha- and beta-D-glucopyranoside; treatment of this mixture with sodium methoxide gives the beta-anomer from which the title aldehyde is obtained in a pure form by transformation of the benzothiazole ring into the formyl group. (C) 2002 Elsevier Science Ltd. All rights reserved.