Organotransition metal modified sugars 4. Carbene complex functionalized acyclic carbohydrates

Abstract

A synthetic strategy based on a combination of sugar electrophiles and transition metal nucleophiles allows the metal carbene functionalization of acyclic carbohydrates. Following this methodology the per- O-acetylated methoxycarbene complexes 8–14 are prepared in moderate to good yields. Upon reaction with ammonia they undergo aminolysis to give the aminocarbene complexes 16–18. 1H-NMR studies indicate that in solution the d-galacto and l-arabino complexes adopt extended planar zigzag conformations. A similar conformational preference is observed for the solid state as established by X-ray studies on the d-galacto derivatives 8 and 15.