An intramolecular conjugate addition of γ-trichloroacetimidoyloxy-α,β-unsaturated esters: a very concise route to daunosamine, acosamine, ristosamine and 3-epi-daunosamine precursors

A new and very concise strategy has been formulated for the synthesis of 3-amino-2,3,6-trideoxyhexoses, daunosamine, acosamine, ristosamine and 3-epi-daunosamine, via cis- and trans-oxazoline intermediates assembled by a novel intramolecular conjugate addition of γ-trichloroacetimidoyloxy-α,β-unsaturated esters in an acyclic system.