A mechanistic investigation of the Pd-catalyzed cross-coupling betweenN-tosylhydrazones and aryl halides

Abstract

The cross-coupling of N-tosylhydrazones and aryl halides forms carbon-carbon bonds, producing 1,1-disubstituted alkenes. Though it has proven extremely useful in several fields of chemistry, its mechanism remains experimentally unexplored. Combining...

Investigating the mechanism and origins of selectivity in palladium-catalysed carbene insertion cross-coupling reactions

“…As expected, the major component is an ion of mass corresponding to the bis-ligated off-cycle oxidative addition resting state (14) with small quantities of another ion (15). Several species of the mass of 15 exist on the proposed catalytic cycle.…”

“…13,14 With N -tosylhydrazones as a diazo substrate precursor, pressurized sample infusion-electrospray ionization-mass spectrometry determined that rate-limiting oxidative addition was exclusive to aryl chlorides, while tentative evidence implied in situ formation of the diazo substrate was turnover determining for aryl bromides and iodides. 15 Newman and co-workers recently used this mechanistic cycle as the basis for their strategy to overcome scope limitations, with slow addition of diazo substrate controlling catalyst speciation and increasing reaction yields. A theoretical study supported oxidative addition of the aryl halide as rate limiting.…”

Computer vision for non-contact monitoring of catalyst degradation and product formation kinetics

“…ATR-IR, Raman), 31 cuvette-based methods ( e.g. UV-vis, calorimetry), 39,40 NMR, 41,42 small angle neutron scattering, 42 mass spectrometry, 43 X-ray diffraction (XRD), 18,36 and auto-sampling for offline gas or liquid chromatography. 44,45 These methods are often used in combination to provide the fullest possible reaction understanding, covering different levels of analyte specificity and limits of detection.…”

Computer Vision for Understanding Catalyst Degradation Kinetics

“…ATR-IR, Raman), 20 cuvettebased methods (e.g. UV-vis, calorimetry), 37,38 NMR, 39,40 small angle neutron scattering, 40 mass spectrometry, 41 X-ray diffraction (XRD), 18,36 and auto-sampling for offline gas or liquid chromatography. 42,43 These methods are often used in combination to provide the fullest possible reaction understanding, covering different levels of analyte specificity and limits of detection.…”