Epimerization of Carbohydrates via Stannylene Acetals. A Practical Synthesis of D-Talose¹

1. Dedicated to the memory of Professor Akira Hasegawa

Abstract

When treated with Bu₂SnO in a suitable solvent, reducing sugars preferentially form 1,2-O-stannylene acetals and, on prolonged treatment with a slight excess of the reagent at reflux temperature, they undergo epimerization. This allows simple preparation of rare monosaccharides from readily available, unprotected starting materials. The process is equilibrium driven, and the equilibrium is shifted largely in favor of structures having an axial hydroxyl group at position 2.

1. Dedicated to the memory of Professor Akira Hasegawa

Notes

1. Dedicated to the memory of Professor Akira Hasegawa

Dedicated to the memory of Professor Akira Hasegawa