Dichotomous Selectivity in Indium-Mediated Aza-Barbier-Type Allylation of 2- N -Acetyl Glycosyl Sulfinylimines in Brine: Convenient Access to Potent Anti-Influenza Agents.

A highly diastereoselective indium-mediated allylation of 2- N -acetyl glycosyl sulfinylimines in brine under mild reaction conditions is reported. The method allows the achievement of a highly remarkable dichotomous selectivity for substrates, providing a single diastereoisomer of the product in 80-98% yield. With chiral ( S )-homoallylic sulfinamide ( R S )- 5 and ( R S )- 8 formed as key intermediates, two potent anti-influenza agents, zanamivir and zanaphosphor, were synthesized in 50% and 41% overall yields, respectively.