Chiral ligands in hypervalent iodine compounds: synthesis and structures of binaphthyl-based λ3-iodanes

Several novel binaphthyl-based chiral hypervalent iodine(III) reagents have been prepared and structurally analyzed. Various asymmetric oxidative reactions were applied to evaluate the reactivities and stereoselectivities of those reagents. Moderate to excellent yields were observed, however, very low stereoselectivities were obtained. The NMR experiments indicate that these reagents are very easily hydrolyzed in either chloroform or DMSO solvents leading to limited stereoselectivities. It is concluded that the use of chiral ligands is an unsuccessful way to prepare efficient stereoselective iodine(III) reagents