Bidentate Nitrogen-Ligated I(V) Reagents, Bi(N)-HVIs: Preparation, Stability, Structure, and Reactivity.

Hypervalent iodine(V) reagents are a powerful class of organic oxidants. While the use of I(V) compounds Dess-Martin periodinane and IBX is widespread, this reagent class has long been plagued by issues of solubility and stability. Extensive effort has been made for derivatizing these scaffolds to modulate reactivity and physical properties but considerable room for innovation still exists. Herein, we describe the preparation, thermal stability, optimized geometries, and synthetic utility of an emerging class of I(V) reagents, Bi(N)-HVIs, possessing datively bound bidentate nitrogen ligands on the iodine center. Bi(N)-HVIs display favorable safety profiles, improved solubility, and comparable to superior oxidative reactivity relative to common I(V) reagents. The highly modular synthesis and in situ generation of Bi(N)-HVIs provides a novel and convenient screening platform for I(V) reagent and reaction development.

Redox deracemization of phosphonate-substituted dihydropyrimidines.

An efficient redox deracemization of the phosphonic ester substituted 3,4-dihydropyrimidin-2-one (DHPM) derivatives is described. The one-pot deracemization strategy consisted of the oxidization to destroy the stereocenter center and the following asymmetric transfer hydrogenation to regenerate the chiral carbon center with the vicinal phosphonic ester group, providing a series of optically active phosphonate substituted DHPMs with up to 96% ee.