Zhang, Wei; Li, Weiyi; Qin, Song published the artcile< Origins of enantioselectivity in the chiral diphosphine-ligated CuH-catalyzed asymmetric hydrosilylation of ketones>, COA of Formula: C19H34O2, the main research area is chiral diphosphine copper hydride catalyzed asym hydrosilylation acetophenone DFT; optimized geometry copper hydride catalyzed asym hydrosilylation acetophenone DFT; silyl ether preparation.
Computational studies on the asym. hydrosilylation of acetophenone over ligated CuH catalysts were performed with the DFT method. The calculations predict that the catalytic reaction involves two steps: (1) CuH addition to the carbonyl group via a four-membered transition state (TS) with the formation of Cu-alkoxide intermediates; (2) regeneration of the ligated CuH catalyst by an external SiH4 through a metathesis process to yield the corresponding silyl ether. The calculations in the chiral diphosphine-ligated CuH systems suggest that the metathesis process is the rate-determining step (RDS). The CuH addition step is vital for the distribution of the racemic products and therefore represents the stereo-controlling step (SCT). In this step, the greater steric hindrance between the aromatic rings of the ligands and the substrate is identified as the major factor for enantioselectivity. The corresponding TS in the face-to-face mode, suffering less steric hindrance, is more stable than its analog in the edge-to-face mode. The enantioselectivities are related not only to the P-Cu-P bite angles in the stereo-controlling TSs, but also to the substituents at the P-aryl rings of the chiral ligands. In short, a larger P-Cu-P bite angle and suitably modified P-aryl rings together are necessary to achieve excellent ee values.
Organic & Biomolecular Chemistry published new progress about Activation energy. 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, COA of Formula: C19H34O2.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics