Xu, Liping; Hilton, Margaret J.; Zhang, Xinhao; Norrby, Per-Ola; Wu, Yun-Dong; Sigman, Matthew S.; Wiest, Olaf published the artcile< Mechanism, Reactivity, and Selectivity in Palladium-Catalyzed Redox-Relay Heck Arylations of Alkenyl Alcohols>, Recommanded Product: (S)-4-(tert-Butyl)-2-(5-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole, the main research area is palladium catalyzed redox relay Heck arylation alkenyl alc mechanism.
The enantioselective Pd-catalyzed redox-relay Heck arylation of acyclic alkenyl alcs. allows access to various useful chiral building blocks from simple olefinic substrates. Mechanistically, after the initial migratory insertion, a succession of β-hydride elimination and migratory insertion steps yields a saturated carbonyl product instead of the more general Heck product, an unsaturated alc. Here, we investigate the reaction mechanism, including the relay function, yielding the final carbonyl group transformation. M06 calculations predict a ΔΔG# of 1 kcal/mol for the site selectivity and 2.5 kcal/mol for the enantioselectivity, in quant. agreement with exptl. results. The site selectivity is controlled by a remote electronic effect, where the developing polarization of the alkene in the migratory insertion transition state is stabilized by the C-O dipole of the alc. moiety. The enantioselectivity is controlled by steric repulsion between the oxazoline substituent and the alc.-bearing alkene substituent. The relay efficiency is due to an unusually smooth potential energy surface without high barriers, where the hydroxyalkyl-palladium species acts as a thermodn. sink, driving the reaction toward the carbonyl product. Computational predictions of the relative reactivity and selectivity of the double bond isomers are validated exptl.
Journal of the American Chemical Society published new progress about Alkenyl alcohols Role: PEP (Physical, Engineering or Chemical Process), PRP (Properties), RCT (Reactant), PROC (Process), RACT (Reactant or Reagent). 1416819-91-4 belongs to class pyridine-derivatives, and the molecular formula is C13H15F3N2O, Recommanded Product: (S)-4-(tert-Butyl)-2-(5-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole.