Synthesis, Structure, and Reactivity of Hypervalent Iodine Reagents Stabilized by Internal Out-of-Plane Halogen Bonding: ortho-Bromo and ortho-Chloro-Substituted [Hydroxy(tosyloxy)iodo]arenes and Iodonium Ylides.

The preparation and reactivity of a series of ortho-halogen-substituted (diacetoxyiodo)arenes, [hydroxy(tosyloxy)iodo]arenes, and aryliodonium ylides are reported. X-ray analysis of 1-[hydroxy(tosyloxy)iodo]-2-bromobenzene confirms the presence of halogen bonds in the intramolecular interactions between the ortho-halogen atom and the hypervalent iodine center, with a normalized contact (observed contact length divided by the sum of the van der Waals radii) value of 0.91. The o-bromo-substituted aryliodonium ylide can be handled and stored at room temperature and can serve as a convenient carbene precursor in a Rh-catalyzed cyclopropanation reaction with styrenes, affording the corresponding cyclopropane products in 59-75% yields.