No abstract

This work reports a modular and rapid approach to the stereoselective synthesis of a variety of α- and β-(1→2)-linked C-disaccharides. The key step is a Ni-catalyzed cross-coupling reaction of D-glucal pinacol boronate with alkyl halide glycoside easily prepared from commercially available D-glucal. The products of this sp(2) -sp(3) cross-coupling reaction can be converted to glucopyranosyl, mannopyranosyl, or 2-deoxy-glucopyranosyl C-mannopyranosides by one- or two-step stereoselective oxidative-reductive transformations. To the best of our knowledge, we demonstrated the first synthetic application of a challenging sp(2) -sp(3) Suzuki-Miyaura cross-coupling reaction in carbohydrate chemistry.

The development of effective protection strategies is essential in the synthesis of complex carbohydrates and glycomimetics. This article describes a versatile four-stage protocol for the synthesis of α- or β-aryl- C -glycosides from unprotected d -glycals using two acetal protecting groups, ethoxyethyl and methoxypropyl, which are stable under harsh basic conditions and convenient for the C-1 metalation of glycals. Their stability was investigated in subsequent cross-coupling reactions with 1-iodonaphthalene followed by oxidative/reductive transformations to naphthyl- C -glycosides.

No abstract

This work represents another step in the effort to use glycals (1,2unsaturated derivatives of carbohydrates) as donor synthons for transition metal-catalyzed arylation reactions. We have employed a novel 1-silyl derivative of d-glucal, which was obtained as ab enchstable solid and could therefore be used conveniently.F or its preparation, we have used at ransient protection with MOP groups, which we developed previously,a nd therefore we could access the key synthon in its unprotected form. Ta king advantage of this, we have carried out ar ange of Hiyama arylation reactions without the need for protection. We have also spectroscopically confirmed the role of the silyl hydride derivative as am asked silanol and its hydrolytic activation, which is ak ey mechanistic step for transmetalation of the glycal moiety to palladium. Moreover,w eh ave used this strategy to develop av ery short synthesis of Dapagliflozin, an important commercial drug.