ENANTIOSELECTIVE HETEROCYCLE FORMATION USING CHIRAL HYPERVALENT IODINE(III)

摘要

The field of chiral hypervalent iodine chemistry has made significant progress in the past decade. This review focuses on enantioselective heterocycle formation induced by chiral hypervalent iodine reagents and catalysts. The enantioselective heterocyclizations are classified into the dearomatization of phenols (and naphthols), alpha-oxidation of carbonyl compounds, and oxidative vicinal difunctionalization of alkenes. As a characteristic reaction of a hypervalent iodine oxidizing reagent, the 6-endo selective lactonization of ortho-alkenylbenzoate is selected and compared with the 5-exo selectivity induced by other electrophilic reagents. The oxidative lactonization with 6-endo selectivity afforded a 4-oxyisochroman-1-one framework, which has been found in a family of polyketide metabolites. The total syntheses of 4-oxyisochroman-1-one natural products were also summarized to assess the synthetic utility of hypervalent iodine compounds.