Eric C. Keske

Hydrogenations at Room Temperature and Atmospheric Pressure with Mesoionic Carbene‐Stabilized Borenium Catalysts

1,2,3-Triazolylidene-based mesoionic carbene boranes have been synthesized in a convenient one-pot protocol from the corresponding 1,2,3-triazolium salts, base, and borane. Borenium ions are obtained by hydride abstraction and serve as catalysts in mild hydrogenation reactions of imines and unsaturated N-heterocycles at ambient pressure and temperature.

Double Single-Crystal-to-Single-Crystal Transformation and Small- Molecule Activation in Rhodium NHC Complexes**

Three gases, one crystal: rhodium NHC complexes undergo back-to-back single-crystal-to-single-crystal transformations by selective nonreversible ligand exchange reactions. Slow diffusion of O(2) converts a dinitrogen complex into a dioxygen complex, and CO subsequently replaces O(2).

CHAPTER 11:Stereospecific and Stereoselective Suzuki–Miyaura Cross-Coupling Reactions

Recent advances in stereospecific and stereoselective Suzuki–Miyaura cross-coupling reactions generating chiral, enantiomerically enriched products are described. In terms of enantioenriched nucleophiles, at the present time, substrates which are effectively coupled in a stereospecific manner are limited to those with C–B bonds that are π-activated (i.e. benzylic, allylic or propargylic), in close proximity to carbonyl compounds, or have a geminal boron substituent. Prior to the work described in this highlight, the Suzuki–Miyaura cross-coupling of chiral organoboron species was limited to cyclopropyl systems. Stereoselective cross-couplings employing enantiopure secondary electrophiles are also rapidly advancing and the use of chiral, racemic electrophiles in conjunction with chiral ligands is an emerging powerful route for the creation of stereochemistry via Suzuki–Miyaura cross coupling. Advances in this area are presented in the second half of this chapter.