Asymmetric Synthesis of Primary Amines via the Spiroborate-Catalyzed Borane Reduction of Oxime Ethers
作者:Xiaogen Huang、Margarita Ortiz-Marciales、Kun Huang、Viatcheslav Stepanenko、Francisco G. Merced、Angel M. Ayala、Wildeliz Correa、Melvin De Jesús
DOI:10.1021/ol0704791
日期:2007.4.1
enantioselective borane reduction of O-benzyloxime ethers to primary amines was studied under catalytic conditions using the spiroborate esters 5-10 derived from nonracemic 1,2-amino alcohols and ethylene glycol. Effective catalytic conditions were achieved using only 10% of catalyst 5 derived from diphenylvalinol in dioxane at 0 degrees C resulting in complete conversion to the corresponding primary amine in
Application of Chiral Mixed Phosphorus/Sulfur Ligands to Enantioselective Rhodium-Catalyzed Dehydroamino Acid Hydrogenation and Ketone Hydrosilylation Processes
作者:David A. Evans、Forrest E. Michael、Jason S. Tedrow、Kevin R. Campos
DOI:10.1021/ja012639o
日期:2003.3.1
Rh-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation reactions (eqs 1, 2). After assaying the influence of the substituents at sulfur, the substituents on the ligand backbone, the relative stereochemistry within the ligand backbone, and the substituents at phosphorus, ligands 2c (R = 3,5-dimethylphenyl) and 3 were found to be optimal in the Rh-catalyzed hydrogenation of a variety of alpha-acylaminoacrylates
Biocatalytic, Intermolecular C−H Bond Functionalization for the Synthesis of Enantioenriched Amides
作者:Soumitra V. Athavale、Shilong Gao、Zhen Liu、Sharath Chandra Mallojjala、Jennifer S. Hirschi、Frances H. Arnold
DOI:10.1002/anie.202110873
日期:2021.11.15
P411 heme enzymes enables intermolecular C−H amidation with high yields and exquisite enantioselectivity. The biocatalytic process utilizes stable hydroxamate esters as nitrenoid precursors and is amenable to scaleup. Mechanistic studies reveal rate-determining nitrenoid formation followed by a stepwise, hydrogen atom transfer-mediated C−Hfunctionalization.
Practical Enantioselective Hydrogenation of α-Aryl- and α-Carboxyamidoethylenes by Rhodium(I)-{1,2-Bis[(<i>o</i>-<i>tert</i>-butoxyphenyl)(phenyl)phosphino]ethane}
作者:Barbara Mohar、Michel Stephan
DOI:10.1002/adsc.201200780
日期:——
The rhodium(I)-1,2-bis[(o-tert-butoxyphenyl)(phenyl)phosphino]ethane} [Rh(I)-(t-Bu-SMS-Phos)] catalyst system displayed prime efficiency in the hydrogenation of large series of α-amidostyrenes and α-amidoacrylates. Up to >99.9% enantiomeric excesses coupled with very high reaction rates were attained operating routinely under 1–10 bar of hydrogen at 22 °C in methanol. Examples include industrial substrates
A Novel Class of P−O Monophosphite Ligands Derived from <scp>d</scp>-Mannitol: Broad Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations
on a new class of P−O monophosphite ligands (designated 3a−k) with a double six-membered-ring backbone onto which are attached additional groups and on applications of their Rh complexes in the hydrogenation of enamides, α-dehydroamino acid esters, dimethyl itaconate, and β-(acylamino)acrylates. Our results demonstrate that the Rh complexes with ligands 3a−k exhibit high enantioselectivity and reactivity