Control of Diastereoselectivity in C=O/C=N Reductive Cyclizations Using an Intramolecularly Tethered Hydrazone

Abstract

Cyclic hydrazones are efficient ketyl radical acceptors in reductive coupling cyclizations mediated by samarium diiodide, ­affording cyclic amino alcohols with controlled stereochemistry at the new aminated stereocenter. This approach has been successfully applied to the stereoselective synthesis of a fully functionalized trehazolin cyclitol starting from d-glucose, where the required cyclic hydrazone was directly obtained by partial hydrazynolysis of a 1,2-cyclic carbonate.