Catalytic Asymmetric Hydrogenation of N-Boc-Imidazoles and Oxazoles
摘要:
Substituted imidazoles and oxazoles were respectively hydrogenated into the corresponding chiral imidazolines and oxazolines (up to 99% ee). The highly enantioselective hydrogenation was achieved by using the chiral ruthenium catalyst, which is generated from Ru(eta(3)-methallyl)(2)(cod) and a trans-chelating chiral bisphosphine ligand, PhTRAP. This is the first successful catalytic asymmetric reduction of 5-membered aromatic rings containing two or more heteroatoms.
A Convenient Synthesis of 2-Oxazolines and 2-Benoxazoles with PPh3-DDQ as the Dehydrating Reagent
作者:Quancai Xu、Zhengning Li、Huiying Chen
DOI:10.1002/cjoc.201190190
日期:2011.5
2‐benoxazoles were synthesized in high yields from acylamino alcohols and acylamino‐ phenols, respectively, with triphenylphosphine‐2,3‐dichloro‐5,6‐dicyanobenzoquinone (PPh3‐DDQ) as the dehydrating and activating reagent. The synthesis was accomplished under neutral conditions.
作者:David S. Laitar、John W. Kramer、Bryan T. Whiting、Emil B. Lobkovsky、Geoffrey W. Coates
DOI:10.1039/b913698c
日期:——
4-Substituted oxazolines, which are readily synthesized from naturally occurring α-amino acids, are converted efficiently and stereospecifically to β-amidoaldehydes in the presence of synthesis gas and catalytic dicobalt octacarbonyl.
Transition metal and base free synthesis of 2-aryl-2-oxazolines from aldehydes and β-amino alcohols catalysed by potassium iodide
作者:C. Uma Maheswari、G. Sathish Kumar、M. Venkateshwar
DOI:10.1039/c4ra08578g
日期:——
Synthesis of 2-aryl-2-oxazolines from β-amino alcohols and aldehydes was achieved in good to excellent yield by employing a potassium iodide (KI)–tert-butyl hydroperoxide (TBHP) catalytic system.
Phosphorus-Based Organocatalysis for the Dehydrative Cyclization of <i>N</i>-(2-Hydroxyethyl)amides into 2-Oxazolines
作者:Farzaneh Soleymani Movahed、Siong Wan Foo、Shogo Mori、Saeko Ogawa、Susumu Saito
DOI:10.1021/acs.joc.1c02318
日期:2022.1.7
substrate scope and higher functional-group tolerance, providing the functionalized 2-oxazolines with retention of the configuration at the C(4) stereogenic center of the 2-oxazolines. Widely accessible β-amino alcohols can be used in this approach, and the cyclization of N-(2-hydroxyethyl)amides provides the desired 2-oxazolines in up to 99% yield. The mechanism of the reaction was studied by monitoring the
Catalytic Asymmetric Hydrogenation of N-Boc-Imidazoles and Oxazoles
作者:Ryoichi Kuwano、Nao Kameyama、Ryuhei Ikeda
DOI:10.1021/ja201543h
日期:2011.5.18
Substituted imidazoles and oxazoles were respectively hydrogenated into the corresponding chiral imidazolines and oxazolines (up to 99% ee). The highly enantioselective hydrogenation was achieved by using the chiral ruthenium catalyst, which is generated from Ru(eta(3)-methallyl)(2)(cod) and a trans-chelating chiral bisphosphine ligand, PhTRAP. This is the first successful catalytic asymmetric reduction of 5-membered aromatic rings containing two or more heteroatoms.