An asymmetric pericyclic cascade approach to 3-alkyl-3-aryloxindoles: generality, applications and mechanistic investigations
作者:Edward Richmond、Kenneth B. Ling、Nicolas Duguet、Lois B. Manton、Nihan Çelebi-Ölçüm、Yu-Hong Lam、Sezen Alsancak、Alexandra M. Z. Slawin、K. N. Houk、Andrew D. Smith
DOI:10.1039/c4ob02526a
日期:——
The reaction of l-serine derived N-arylnitrones with alkylarylketenes generates 3-alkyl-3-aryloxindoles in good yields and excellent enantioselectivities.
Metal‐Free Hydrosilylation of Ketenes with Silicon Electrophiles: Access to Fully Substituted Aldehyde‐Derived Silyl Enol Ethers
作者:Avijit Roy、Martin Oestreich
DOI:10.1002/chem.202100877
日期:2021.6.4
catalysts is reported. The boron Lewis acid tris(pentafluorophenyl)borane accelerates the slow uncatalyzed reaction of ketenes and hydrosilanes, thereby providing a convenient access to the new class of β,β-di- and β-monoaryl-substituted aldehyde-derived silyl enolethers. Yields are moderate to high, and Z configuration is preferred. The corresponding silyl bis-enol ethers are also available when using
Access to Quaternary Stereogenic Centers via Rhodium(III)-Catalyzed Annulations between 2-Phenylindoles and Ketenes
作者:Xifa Yang、Yunyun Li、Lingheng Kong、Xingwei Li
DOI:10.1021/acs.orglett.8b00497
日期:2018.4.6
Rh(III)-catalyzed C–H activation of arenes and mild oxidative [4 + 2] annulative coupling with ketenes have been realized. The uniquely high reactivity of the C(3) of 2-phenylindoles was successfully utilized to facilitate the reductive elimination process, leading to efficient synthesis of cyclic products with a quaternary carbon stereocenter.
Catalytic Asymmetric Synthesis of Esters from Ketenes
作者:Sheryl L. Wiskur、Gregory C. Fu
DOI:10.1021/ja0506152
日期:2005.5.1
By building on elementary principles of Brønsted acid-base chemistry, a nucleophile-catalyzed method for the asymmetric synthesis of esters fromketenes has been transformed into a much more versatile and effective Brønsted acid-catalyzed process. The product aryl esters can be converted into useful derivatives, such as enantioenriched alcohols and carboxylic acids.
Stereo‐ and Chemodivergent NHC‐Promoted Functionalisation of Arylalkylketenes with Chloral
作者:James J. Douglas、Gwydion Churchill、Alexandra M. Z. Slawin、David J. Fox、Andrew D. Smith
DOI:10.1002/chem.201503308
日期:2015.11.9
Stereo‐ and chemodivergent enantioselective reaction pathways are observed upon treatment of alkylarylketenes and trichloroacetaldehyde (chloral) with N‐heterocyclic carbenes, giving selectively either β‐lactones (up to 88:12 dr, up to 94 % ee) or α‐chloroesters (up to 94 % ee). Either 2‐arylsubstitution or an α‐branched iPr alkyl substituent within the ketene favours the chlorination pathway, allowing