Enantioselective Synthesis of Nitrogen Heterocycles Using Chiral Hypervalent Iodine Reagents

Abstract

Hypervalent iodine compounds have emerged in recent years as versatile reagents for oxidative transformations. They may be added to a reaction in stoichiometric amounts or generated in situ from an appropriate iodide and an external oxidant. In the latter case the iodide can be used in catalytic amounts, which is particularly helpful when more expensive or difficult to prepare chiral reagents are required. Polyvalent iodine compounds have found many applications in synthesis. They are used mainly as oxidants and as electrophilic reagents. Some of the reagents and catalysts used in the enantioselective synthesis of nitrogen heterocycles were initially developed for other purposes, others are new. Polyvalent iodine(III) compounds may be used to functionalize alkenes. The enantioselective formation of C—N bonds has not been very much explored yet, but the examples known show the potentialities of the technique.