A general, iterative, and modular approach toward carbohydrate libraries based on ruthenium-catalyzed oxidative cyclizations.

Carbohydrates are an omnipresent class of highly oxygenated natural products. Due to their wide spectra of biological activities, they have been in the center of synthetic organic chemistry for more than 130 years. During the past 50 years non-natural carbohydrates attracted the interest of various chemists in the fields of organic, biological, and medical chemistry.

Concise approach to the "higher sugar" core of the nucleoside antibiotic hikizimycin.

A highly productive synthesis of phenylthio glycoside 33 is described which constitutes a fully functional surrogate for the hikosamine core of hikizimycin 1, a complex nucleoside antibiotic endowed with promising anthelmintic properties. The chosen approach to this undecose derivative starts from mannofuranose 7 which was one-carbon homologated to alkyne 8 in one step on treatment with lithio (trimethylsilyl)diazomethane. Alkynyl iodide 12 derived from 8 was combined with the tartrate-derived aldehyde 17 by a Nozaki-Hiyama-Kishi reaction that can either be performed using overstoichiometric amounts of CrCl2 or by means of a catalytic manifold based on the turnover of a cat.