Gram‐Scale Preparation of a p‐(C‐Glucopyranosyl)‐ L ‐phenylalanine Derivative by a Negishi Cross‐Coupling Reaction

A p‐(C‐glucopyranosyl)‐L‐phenylalanine derivative protected to be directly incorporated into a peptidic chain is prepared in 37 % yield from glucose on a gram scale, with a Negishi cross‐coupling reaction as the key step. Zincated glucal and p‐iodo‐L‐phenylalanine are involved in this organometallic coupling, which gives rise to a link between the sugar and amino acid moieties in 90 % yield; the β‐gluco configuration of the C‐glycopyranosyl amino acid is ascertained by a stereoselective hydroboration of the double bond of the glucal. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)