94942-89-9Relevant articles and documents
Effect of support texture on enantioselective hydrogenation of (E)-α-phenylcinnamic acid with cinchonidine-modified palladium catalysts
Nitta, Yuriko,Okamoto, Yasuaki
, p. 1115 - 1116 (1998)
The texture of support materials has decisive influence on the behavior of cinchonidine-modified palladium catalysts in the enantioselective hydrogenation of (E)-α-phenylcinnamic acid, which suggests an important role of pore diffusion in the determinatio
Metal-Free Hydrosilylation of Ketenes with Silicon Electrophiles: Access to Fully Substituted Aldehyde-Derived Silyl Enol Ethers
Roy, Avijit,Oestreich, Martin
supporting information, p. 8273 - 8276 (2021/05/11)
Little-explored hydrosilylation of ketenes promoted by main-group catalysts is reported. The boron Lewis acid tris(pentafluorophenyl)borane accelerates the slow uncatalyzed reaction of ketenes and hydrosilanes, thereby providing a convenient access to the new class of β,β-di- and β-monoaryl-substituted aldehyde-derived silyl enol ethers. Yields are moderate to high, and Z configuration is preferred. The corresponding silyl bis-enol ethers are also available when using dihydrosilanes. The related trityl-cation-initiated hydrosilylation involving self-regeneration of silylium ions is far less effective.
Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary α-Hydroxy Esters
Greenhalgh, Mark D.,Laina-Martín, Víctor,Neyyappadath, Rifahath M.,Qu, Shen,Smith, Andrew D.,Smith, Samuel M.
supporting information, p. 16572 - 16578 (2020/09/09)
A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.
