A survey of chiral hypervalent iodine reagents in asymmetric synthesis.

Soumen Ghosh,Indranil Chatterjee,Suman Pradhan

doi:10.3762/bjoc.14.107

Abstract

The recent years have witnessed a remarkable growth in the area of chiral hypervalent iodine chemistry. These environmentally friendly, mild and economic reagents have been used in catalytic or stoichiometric amounts as an alternative to transition metals for delivering enantioenriched molecules. Varieties of different chiral reagents and their use for demanding asymmetric transformations have been documented over the last 25 years. This review highlights the contribution of different chiral hypervalent iodine reagents in diverse asymmetric conversions.

Highlights

It is more than one century ago since the discovery of the first hypervalent iodine reagent (HIR) [1] and hypervalent iodine chemistry has started to flourish as one of the important and leading areas in organic synthesis
The ongoing demand of modern synthetic chemistry for the development of catalytic enantioselective C–C bond formation reactions turned the attention of the scientific community towards the evolution of new chiral hypervalent iodine reagents
This review points a number of striking chiral hypervalent iodine reagents used in stoichiometric or in catalytic fashion for quite a number of useful organic transformations

Summary

Introduction

It is more than one century ago since the discovery of the first hypervalent iodine reagent (HIR) [1] and hypervalent iodine chemistry has started to flourish as one of the important and leading areas in organic synthesis. To ensure asymmetric transformations, the same group developed the synthesis of more effective chiral iodonium salts 16 which were used for the α-arylation of β-ketoester to deliver α-arylated β-ketoesters with moderate enantioselectivity (Scheme 17) [63] This was the first example of an asymmetric α-arylation of β-ketoesters using hypervalent iodine reagents. Ishihara’s catalyst was modified by using an (S)-proline derivative to achieve a high level of enantioselectivity in the presence of peracetic acid (Scheme 21) [70] They postulated the formation of possible intermediate 97 which favored the nucleophilic attack of the aryl ring from the less sterically hindered side. Scheme 25: Alkynylation of β-ketoesters and dearomative alkynylation of phenols

Conclusion

Findings

58. For a racemic version of the same rearrangement