163380-15-2Relevant articles and documents
Double Asymmetric Hydrogenation of α-Iminoketones: Facile Synthesis of Enantiopure Vicinal Amino Alcohols
Lin, Xin,Shao, Pan-Lin,Song, Jingyuan,Wang, Jiang,Wen, Jialin,Zhang, Xumu
, p. 12729 - 12735 (2021/10/29)
This study presents an Rh/DuanPhos-catalyzed double asymmetric hydrogenation of α-iminoketones for accessing chiral vicinal amino alcohols, which are privileged motifs in pharmaceuticals, agrochemicals, fine chemicals, chiral auxiliaries, organocatalysts, etc. Compared with existing methods, this methodology has the following advantages, such as one-pot operation, high efficiency, operational simplicity, limited waste, broad reaction scope, and high yields (90 to 96%) and stereoselectivities (up to >99:1 dr; >99.9% ee). In addition, the mechanism of the transformation was revealed to be a stepwise reaction by isolating and analyzing reaction intermediates.
Lutidine-Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones
Zhang, Linli,Tang, Yitian,Han, Zhaobin,Ding, Kuiling
supporting information, p. 4973 - 4977 (2019/03/17)
A series of MnI complexes containing lutidine-based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional-group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth-abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs. Preliminary mechanistic investigations indicate that an outer-sphere mode of substrate–catalyst interactions probably dominates the catalysis.
Total synthesis of ezetimibe, a cholesterol absorption inhibitor
Sniezek, Marcin,Stecko, Sebastian,Panfil, Irma,Furman, Bartlomiej,Chmielewski, Marek
, p. 7048 - 7057 (2013/08/23)
Ezetimibe (1), a strong β-lactamic cholesterol absorption inhibitor, was synthesized from (R)-6-(4-fluorophenyl)-5,6-dihydro-2H-pyran-2-one 7. Independent pathways were analyzed in order to select the optimal one, which involved 1,3-dipolar cycloaddition with C-(4-benzyloxyphenyl)-N-(4-fluorophenyl) -nitrone (8), intramolecular nucleophilic displacement at the benzylic position of the lactone, cleavage of the N-O bond, elimination of a water molecule, hydrogenation of the double bond, rearrangement of the six-membered lactone ring into a β-lactam moiety, and final deprotection of the phenolic hydroxyl group. Highly stereoselective Sc(OTf)3-catalyzed 1,3-dipolar cycloaddition was the most crucial step of the synthesis. Owing to the rigid transition state of the cycloaddition, the absolute configuration of the starting lactone controlled the formation of other stereogenic centers of the final molecule 1.