Enantioselective Mannich Reaction of β-Keto Esters with Aromatic and Aliphatic Imines Using a Cooperatively Assisted Bifunctional Catalyst
作者:Antti J. Neuvonen、Petri M. Pihko
DOI:10.1021/ol5025025
日期:2014.10.3
An efficient urea-enhanced thiourea catalyst enables the enantioselective Mannichreaction between β-keto esters and N-Boc-protected imines under mild conditions and minimal catalyst loading (1–3 mol %). Aliphatic and aromatic substituents are tolerated on both reaction partners, affording the products in good enantiomeric purity. The corresponding β-amino ketones can readily be accessed via decarboxylation
One-Pot Synthesis of α-Amino Acids from CO<sub>2</sub> Using a Bismetal Reagent with Si–B Bond
作者:Tsuyoshi Mita、Jianyang Chen、Masumi Sugawara、Yoshihiro Sato
DOI:10.1021/ol302952r
日期:2012.12.21
TsOH·H2O, precursors of N-Boc-imines can be converted into the corresponding α-aryl or α-alkenyl glycine derivatives under gaseous CO2 in moderate-to-high yields with a single operation. α-Isobutenyl glycine thus obtained can be further derivatized into various types of α-aminoacids including N-Boc-leucine, serine, and glycine derivatives in short steps.
Asymmetric Aminalization via Cation-Binding Catalysis
作者:Sang Yeon Park、Yidong Liu、Joong Suk Oh、Yoo Kyung Kweon、Yong Bok Jeong、Mengying Duan、Yu Tan、Ji-Woong Lee、Hailong Yan、Choong Eui Song
DOI:10.1002/chem.201703800
日期:2018.1.24
Asymmetric cation‐binding catalysis, in principle, can generate “chiral” anionic nucleophiles, where the counter cations are coordinated within chiral environments. Nitrogen nucleophiles are intrinsically basic, therefore, its use as nucleophiles is often challenging and limiting the scope of the reaction. Particularly, a formation of configurationally labile aminal centers with alkyl substituents
Two Distinct Ag(I)- and Au(I)-Catalyzed Olefinations between α-Diazo Esters and <i>N</i>-Boc-Derived Imines
作者:Rahul Dadabhau Kardile、Rai-Shung Liu
DOI:10.1021/acs.orglett.9b02343
日期:2019.8.16
Metal-catalyzed reactions between α-diazo esters and imines were well-known to yield aziridine derivatives exclusively. This work reports two newolefinationreactions between N-Boc-derived (Boc = tert-Butyloxycarbonyl) imines and α-diazo esters with Ag(I) and Au(I) catalysts, respectively. Our mechanistic studies reveal that these newolefinations involve an initial attack of diazo esters on metal/imine
One-Pot Catalytic Enantioselective Synthesis of Tetrahydropyridines via a Nitro-Mannich/Hydroamination Cascade
作者:David M. Barber、Hitesh J. Sanganee、Darren J. Dixon
DOI:10.1021/ol302459c
日期:2012.10.19
The highly enantioselective preparation of synthetically useful tetrahydropyridine derivatives employing a one-pot nitro-Mannich/hydroamination cascade is reported. This approach utilizes an asymmetric organocatalytic nitro-Mannich reaction followed by a gold-catalyzed alkyne hydroamination/isomerization sequence that yields the desired tetrahydropyridines in good yields and high diastereo- and enantioselectivities