61586-46-7Relevant articles and documents
Rhodium-catalyzed asymmetric hydrogenation of β-cyanocinnamic esters with the assistance of a single hydrogen bond in a precise position
Li, Xiuxiu,You, Cai,Yang, Yusheng,Yang, Yuhong,Li, Pan,Gu, Guoxian,Chung, Lung Wa,Lv, Hui,Zhang, Xumu
, p. 1919 - 1924 (2018/02/23)
With the assistance of hydrogen bonds, the first asymmetric hydrogenation of β-cyanocinnamic esters is developed, affording chiral β-cyano esters with excellent enantioselectivities (up to 99% ee). This novel methodology provides an efficient and concise synthetic route to chiral GABA-derivatives such as (S)-Pregabalin, (R)-Phenibut, (R)-Baclofen. Interestingly, in this system, the catalyst with a single H-bond donor performs better than that with double H-bond donors, which is a novel discovery in the metalorganocatalysis area.
Catalytic asymmetric michael reactions of acetaldehyde
Garcia-Garcia, Patricia,Ladepeche, Arnaud,Halder, Rajkumar,List, Benjamin
supporting information; experimental part, p. 4719 - 4721 (2009/02/06)
(Chemical Equation Presented) Acetaldehyde, now a big contender: A silyl prolinol derivative was found to catalyze the first Michael addition of acetaldehyde with both aromatic and aliphatic nitroolefins in excellent enantioselectivities (see scheme, TMS = trimethylsilyl). The utility of the reaction is illustrated in the synthesis of three current pharmaceuticals and in the synthesis of an enantiopure 3-monosubstituted pyrrolidine.
Asymmetric nitroalkene [4 + 2] cycloadditions: Enantioselective synthesis of 3-substituted and 3,4-disubstituted pyrrolidines
Denmark,Marcin
, p. 3221 - 3235 (2007/10/02)
2-Substituted 1-nitroalkenes undergo highly diastereoselective, Lewis-acid-promoted, [4 + 2] cycloaddition with chiral vinyl ethers derived from (R)-2,2-diphenylcyclopentanol and (1R,2S)-2-phenylcyclohexanol to afford cyclic nitronates in high yields. The resulting nitronates were reduced with hydrogen at 160 psi in the presence of platinum oxide to afford enantiomerically enriched pyrrolidines (both as the free base and N-protected derivatives) in good yields. A series of 3-substituted pyrrolidines (71-97% ee) were prepared, as well as (3S,4R)-4-methyl-3-phenyl-N-(p-tolylsulfonyl)pyrrolidine (92% ee) and (3S,4S)-3,4-diphenylpyrrolidine (99% ee). The chiral auxiliaries can be recovered in nearly quantitative yields after hydrogenation.
