The Direct Organocatalytic Asymmetric Mannich Reaction: Unmodified Aldehydes as Nucleophiles.
نویسندگان
چکیده
منابع مشابه
The direct organocatalytic asymmetric mannich reaction: unmodified aldehydes as nucleophiles.
The unprecedented application of unmodified aldehydes as nucleophilic donors in direct catalytic asymmetric Mannich-type reactions is disclosed in a full account. Our efforts in broadening the applicability of chiral pyrrolidine-based catalysts in direct asymmetric Mannich-type reactions led to the highly diastereo- and enantioselective and concise synthesis of functionalized alpha- and beta-am...
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A direct asymmetric Mannich reaction of N-unprotected 3-bromooxindoles with N-Ts-imines catalyzed by bifunctional thiourea derived from 2-substituted cinchona alkaloid was developed. Products with vicinal chiral tertiary and brominated quaternary stereogenic centers were achieved in excellent diastereo- and enantioselectivity (up to 99 : 1 dr, 99% ee).
متن کاملThermal effects in the organocatalytic asymmetric Mannich reaction.
The proline-catalyzed direct asymmetric Mannich reaction between cyclohexanone, formaldehyde, and various anilines is thermally accelerated. With only 0.5 mol % of catalyst, Mannich products with up to 98% ee have been obtained after a short period of time in reactions performed under microwave irradiation. In situ reduction of the resulting ketones affords N-aryl amino alcohols in up to 86% yi...
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We reported the first enzyme-catalysed, direct, three-component asymmetric Mannich reaction using protease type XIV from Streptomyces griseus (SGP) in acetonitrile. Yields of up to 92% with enantioselectivities of up to 88% e.e. and diastereoselectivities of up to 92:8 (syn:anti) were achieved under the optimised conditions. This enzyme's catalytic promiscuity expands the application of this bi...
متن کامل3-Pyrrolidinecarboxylic acid for direct catalytic asymmetric anti-Mannich-type reactions of unmodified ketones.
We report the development of direct catalytic, enantioselective, anti-selective Mannich-type reactions between unmodified ketones and alpha-imino esters under mild conditions. The reactions were performed using 5-10 mol % of (R)-3-pyrrolidinecarboxylic or (R)-beta-proline as catalyst in an environmentally benign solvent, 2-PrOH, at room temperature. The anti-Mannich products were obtained in go...
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ژورنال
عنوان ژورنال: ChemInform
سال: 2004
ISSN: 0931-7597,1522-2667
DOI: 10.1002/chin.200417035