A survey of chiral hypervalent iodine reagents in asymmetric synthesis

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.

A Continuum from Halogen Bonds to Covalent Bonds: Where Do λ3 Iodanes Fit?

“…Hypervalent iodine compounds (HVI) are important alternatives to transition metal reagents because of their reactivity, synthetic utility, low cost, abundance, and non-toxic nature [1][2][3][4][5][6]. HVIs are involved in a multitude of reactions such as: reductive elimination, ligand exchange, oxidative addition, and ligand coupling [7,8]. The three-center four-electron bonds (3c-4e) in HVI are weak and polarizable, which is valuable in synthetic organic chemistry, as they can exchange leaving groups or accept electrophilic/nucleophilic ligands depending on their surroundings [9].…”

Asymmetric [N–I–N]+ halonium complexes

“…Similarly, the effectiveness of asymmetric reagents in producing asymmetrically pure compounds has been realised and research into new variations is rampant in the literature. 11,12 Therefore, the potential of asymmetric halonium reagents is a tempting target for modern synthetic chemists to explore. However, to date all reported halonium complexes (and even linear [AgL 2 ] + analogues) have involved a pair of homoleptic ligands, [13][14][15][16][17] with no unrestrained heteroleptic examples being described, though ligand enforced examples have been previously observed in solution.…”

Carbohydrate-Based Chiral Iodoarene Catalysts: A Survey through the Development of an Improved Catalyst Design

“…Kita and coworkers developed a method for the enantioselective dearomatization of naphthole derivatives like compound 1 (Scheme 1) to the corresponding spiro lactone 2 using the chiral iodoarene catalyst 3 (Figure 1) and stoichiometric amounts of oxidant [14]. In the meantime, the iodoarene catalysts 4 – 7 (Figure 1) have been developed and were used in effective enantioselective dearomatizations of naphthole derivatives [15,16,17,18,19].…”