Enantioselective Construction of Quaternary Stereogenic Centers by the Addition of an Acyl Anion Equivalent to 1,3-Dienes
作者:Nathan J. Adamson、Sangjune Park、Pengfei Zhou、Andrew L. Nguyen、Steven J. Malcolmson
DOI:10.1021/acs.orglett.0c00412
日期:2020.3.6
We report the enantioselective formation of quaternary stereogenic centers by the intermolecular addition of malononitrile, an acyl anion equivalent, and related pronucleophiles to several 1,3-disubstituted acyclic 1,3-dienes in the presence of a Pd-PHOX catalyst. Products are obtained in up to 88% yield and 99:1 er and in most cases are formed as a single regioisomer. The products' malononitrile unit
Optically Active Bicyclic N-Heterocycles by Organocatalytic Asymmetric Michael Addition/Cyclization Sequences
作者:Dennis Worgull、Gustav Dickmeiss、Kim L. Jensen、Patrick T. Franke、Nicole Holub、Karl Anker Jørgensen
DOI:10.1002/chem.201100233
日期:2011.4.4
Highly stereoselective one‐pot syntheses of various opticallyactive N‐heterocyclic bicycles have been developed. The protocols are based on an organocatalytic, asymmetric Michael addition followed by a condensation/cycloaddition sequence to furnish aziridine carbonyls, β‐lactams, or octahydrobenzo[c]isoxazoles depending on the reaction conditions and applied nucleophiles.
已开发出各种光学活性N杂环自行车的高度立体选择性单锅合成器。该方案基于有机催化,不对称迈克尔加成,然后进行缩合/环加成序列,以根据反应条件和所应用的亲核试剂提供氮丙啶羰基,β-内酰胺或八氢苯并[ c ]异恶唑。
Enantioselective Intermolecular Pd-Catalyzed Hydroalkylation of Acyclic 1,3-Dienes with Activated Pronucleophiles
作者:Nathan J. Adamson、Katherine C. E. Wilbur、Steven J. Malcolmson
DOI:10.1021/jacs.7b13300
日期:2018.2.28
We report a highly enantioselective Pd-PHOX-catalyzed intermolecular hydroalkylation of acyclic1,3-dienes. Meldrum's acid derivatives and other activated C-pronucleophiles, such as β-diketones and malononitriles, react with a variety of aryl- and alkyl-substituted dienes in ≤20 h at room temperature. The coupled products, obtained in up to 96% yield and 97.5:2.5 er, are easily transformed into useful
3-Butyl-1-methylimidazolinium borohydride ([bmim][BH4])—a novel reducing agent for the selective reduction of carbon–carbon double bonds in activated conjugated alkenes
A novel ionic reducing reagent, 3-butyl-1-methylimidazolium borohydride ([bmim][BH4]), was synthesized and successfully used for the selective reduction of carbon–carbondoublebonds in conjugated alkenes as well as the α,β-carbon–carbon doublebonds in highly activated α,β,γ,δ-unsaturated alkenes. The reagent can be regenerated and reused several times without losing its activity.
A Convenient Heterogeneous Reduction of Knoevenagel Product by Hantzsch Ester and Its Development into Reductive Alkylation of Malononitrile
作者:Yong-Qing Yang、Zheng Lu
DOI:10.1002/cjoc.201400144
日期:2014.7
Poor solubility of Hantzschester is used as indicator in the reduction of methylidene malononitrile. The Knoevenagel reaction is integrated to develop a reductivealkylation of malononitrile with aryl and aliphatic aldehyde as the carbonyl substrate.