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
[4+2] Cycloaddition of Ketenes with<i>N</i>-Benzoyldiazenes Catalyzed by N-Heterocyclic Carbenes
作者:Xue-Liang Huang、Lin He、Pan-Lin Shao、Song Ye
DOI:10.1002/anie.200804487
日期:2009.1
Enantioselectivity switch: A catalytic enantioselective [4+2] cycloaddition reaction of alkylarylketenes with N‐aryl‐N′‐benzoyldiazenes or N,N′‐dibenzoyldiazenes to give 1,3,4‐oxadiazin‐6‐ones 1 was developed by employing N‐heterocyclic carbene (NHC) catalysts. The enantioselectivities could be switched for most reactions by changing the substituents on the NHC catalyst. TBS=tert‐butyldimethylsilyl
Enantioselective formal [2+2] cycloaddition of ketenes with nitroso compounds catalyzed by N-heterocyclic carbenes
作者:Tong Wang、Xue-Liang Huang、Song Ye
DOI:10.1039/c0ob00249f
日期:——
Chiral N-heterocycliccarbenes were found to be efficient catalysts for the formal [2+2] cycloaddition reaction of alkyl(aryl)ketenes and nitroso compounds to give the corresponding 1,2-oxazetidin-3-ones in moderate to good yields with high enantioselectivities. Reductive ring-opening of the oxazetidinones give the corresponding α-hydroxy acid derivatives in good yields.
Lewis Acid Catalyzed Formal (3+2)‐Cycloaddition of Bicyclo[1.1.0]butanes with Ketenes
作者:Niklas Radhoff、Constantin G. Daniliuc、Armido Studer
DOI:10.1002/anie.202304771
日期:2023.8.21
efficient and transition-metal-free method for the preparation of valuable bicyclo[2.1.1]hexanes by Lewisacid catalyzed formal (3+2)-cycloaddition of readily available bicyclo[1.1.0]butanes and ketenes is presented. Excellent tolerance towards functional groups and versatile substitution patterns in the 3-position of the bicyclo[2.1.1]hexane core are demonstrated.