Catalyst-controlled Asymmetric Syntheses of Organoselenium Compounds. β-Hydroxyselenides by Desymmetrization of meso Epoxides

β-Hydroxy selenides are efficient intermediates for a variety of synthetic transformations. As depicted in Scheme 1 together with classical reactions, such as the reduction to alcohols 1 (path a) or the oxidation to allylic alcohols 1 (path b), simple and convenient conversions into tetrahydrofurans, 2 1,3-oxazolidinones, 3 amino alcohols 3 and β-aryl selenides 4 have been recently reported in the literature. The key step of most of these multi-step procedures consists in the removal of the organoselenium moiety which occurs in radical or ionic conditions and generates substitution (path d) or cyclization products (path c and e). The interesting selenium-assisted substitution of the hydroxyl group by an aromatic compound (path f) or by other carbon nucleophiles 5 has also been recently described. It must be underlined that the products generated from enantiomerically enriched β-hydroxy selenides are obtained without any loss of the enantiomeric purity.