Front Cover Picture: Tetrahydropyran-Based Hybrid Dipeptides as Asymmetric Catalysts for Michael Addition of Aldehydes to β-Nitrostyrenes (Adv. Synth. Catal. 4/2017)
نویسندگان
چکیده
منابع مشابه
Proline-based reduced dipeptides as recyclable and highly enantioselective organocatalysts for asymmetric Michael addition.
A series of novel proline-based reduced dipeptides was developed and evaluated for a direct Michael addition of ketones and aldehydes to nitroalkenes. Excellent yields (up to 95%), diastereoselectivities (up to 98% dr) and enantioselectivities (up to 98% ee) were achieved in the presence of 5 mol% catalyst without any additional additives at room temperature.
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The application of six novel α,β-dipeptides as chiral organocatalysts in the asymmetric Michael addition reaction between enolizable aldehydes and N-arylmaleimides or nitroolefins is described. With N-arylmaleimides as substrates, the best results were achieved with dipeptide 2 as a catalyst in the presence of aq. NaOH. Whereas dipeptides 4 and 6 in conjunction with 4-dimethylaminopyridine (DMA...
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To map out the efficient organocatalyst requirements in the Michael addition of 1,3-dicarbonyl indane compounds to nitrostyrenes, a dozen different amino organocatalysts containing a p-toluenesulfonyl group (Ts) have been evaluated; excellent enantio-selectivities (up to er 92:8) were obtained with a primary amine-based Ts-DPEN catalyst and a plausible catalytic reaction mechanism was proposed ...
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The conjugate addition of Ni(II) complexes of glycine Schiff base to α,β-unsaturated aldehydes catalyzed by (S)-2-(diphenyl(trimethylsilyloxy)methyl)pyrrolidine afforded adducts in excellent yields with up to 49:1 dr and 95% ee. This method enables the construction of two adjacent chiral centers in one step, and offers an alternative route to chiral α-amino acid derivatives.
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ژورنال
عنوان ژورنال: Advanced Synthesis & Catalysis
سال: 2017
ISSN: 1615-4150
DOI: 10.1002/adsc.201700090