65651-63-0Relevant articles and documents
Combining prolinamides with 2-pyrrolidinone: Novel organocatalysts for the asymmetric aldol reaction
Vlasserou, Ismini,Sfetsa, Maria,Gerokonstantis, Dimitrios-Triantafyllos,Kokotos, Christoforos G.,Moutevelis-Minakakis, Panagiota
, p. 2338 - 2349 (2018/04/06)
Peptides and especially prolinamides have been identified as excellent organocatalysts for the aldol reaction. The combination of prolinamides with derivatives bearing the 2-pyrrolidinone scaffold, deriving from pyroglutamic acid, led to the identification of novel organocatalysts for the intermolecular asymmetric aldol reaction. The new hybrids were tested both in organic and aqueous media. Among the compounds tested, 22 afforded the best results in petroleum ether, while 25 afforded the products in brine in high yields and selectivities. Then, various ketones and aldehydes were utilized and the products of the aldol reaction were obtained in high yields (up to 100%) with excellent diastereo- (up to 97:3 dr) and enantioselectivities (up to 99% ee).
Highly enantioselective direct asymmetric aldol reaction catalyzed by 4,5-methano-L-proline
Zhang, Yukun,Zhu, Jun,Yu, Na,Yu, Han
supporting information, p. 171 - 174 (2015/03/04)
The 4,5-methano-L-proline was used as chiral organocatalysts in direct asymmetric aldol reactions. Under the optimal conditions, excellent enantioselectivities (up to 99% ee) were obtained with high chemical yields (up to 95%) for a series of aldehydes using only 5 mol% catalyst loading. To show the practicality of the method, the reaction was tested at a large scale. The reaction was complete in 16 h, and the aldol product was obtained in 86% yield and 93% ee.
Asymmetric Catalysis with Ethylene. Synthesis of Functionalized Chiral Enolates
Biswas, Souvagya,Page, Jordan P.,Dewese, Kendra R.,RajanBabu
supporting information, p. 14268 - 14271 (2015/12/01)
Trialkylsilyl enol ethers are versatile intermediates often used as enolate surrogates for the synthesis of carbonyl compounds. Yet there are no reports of broadly applicable, catalytic methods for the synthesis of chiral silyl enol ethers carrying latent functionalities useful for synthetic operations beyond the many possible reactions of the silyl enol ether moiety itself. Here we report a general procedure for highly catalytic (substrate:catalyst ratio up to 1000:1) and enantioselective (92% to 98% major enantiomer) synthesis of such compounds bearing a vinyl group at a chiral carbon at the β-position. The reactions, run under ambient conditions, use trialkylsiloxy-1,3-dienes and ethylene (1 atm) as precursors and readily available (bis-phosphine)-cobalt(II) complexes as catalysts. The silyl enolates can be readily converted into novel enantiopure vinyl triflates, a class of highly versatile cross-coupling reagents, enabling the syntheses of other enantiomerically pure, stereodefined trisubstituted alkene intermediates not easily accessible by current methods. Examples of Kumada, Stille, and Suzuki coupling reactions are illustrated.
