<i>syn</i>
‐Selective Michael Reaction of α‐Branched Aryl Acetaldehydes with Nitroolefins Promoted by Squaric Amino Acid Derived Bifunctional Brønsted Bases
作者:Ane García‐Urricelqui、Abel Cózar、Teresa E. Campano、Antonia Mielgo、Claudio Palomo
DOI:10.1002/ejoc.202100355
日期:2021.7.7
α-Branched aryl acetaldehydes are efficiently activated by a cinchona based squaric acid-derived peptide to provide, upon reaction with nitroolefins, 2,2,3-trisubstituted syn γ-nitroaldehydes with high diastereo- and enantioselectivity.
Michaeladditions of different aldehydes and ketones to β-nitrostyrene and 2-(β-nitrovinyl)thiophene in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) were studied. β-Nitrostyrene was a better acceptor than 2-(β-nitrovinyl)thiophene, in terms of both reactivity and selectivity. Aldehydes proved to be better donors than ketones, which were themselves better than β-diketones. L-proline proved
Pyrrolidinyl-Camphor Derivatives as a New Class of Organocatalyst for Direct Asymmetric Michael Addition of Aldehydes and Ketones to β-Nitroalkenes
作者:Ying-Fang Ting、Chihliang Chang、Raju Jannapu Reddy、Dhananjay R. Magar、Kwunmin Chen
DOI:10.1002/chem.201000483
日期:——
Practical and convenient synthetic routes have been developed for the synthesis of a new class of pyrrolidinyl–camphor derivatives (7 a–h). These novel compounds were screened as catalysts for the direct Michael addition of symmetrical α,α‐disubstituted aldehydes to β‐nitroalkenes. When this asymmetric transformation was catalyzed by organocatalyst 7 f, the desired Michael adducts were obtained in
The role of reversibility in the enantioselective conjugate addition of α,α-disubstituted aldehydes to nitro-olefins catalyzed by primary amine thioureas
作者:Yining Ji、Donna G. Blackmond
DOI:10.1039/c4cy00648h
日期:——
Identification of intermediates in the asymmetric conjugate addition of aldehdyes to nitro-olefins catalyzed by primary amine thioureas add mechanistic insight.
通过主要胺硫脲催化的醛类向硝基烯烃的不对称共轭加成,识别了中间体,增加了对机理的理解。
A Chiral Primary Amine Thiourea Catalyst for the Highly Enantioselective Direct Conjugate Addition of α,α-Disubstituted Aldehydes to Nitroalkenes
作者:Mathieu P. Lalonde、Yonggang Chen、Eric N. Jacobsen