Control of N‐Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole‐γ‐Amino Acid Derivatives |
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| Authors: | Dr Xiang‐Yu Chen Jia‐Wen Xiong Qiang Liu Sun Li He Sheng Dr Carolina von?Essen Prof?Dr Kari Rissanen Prof?Dr Dieter Enders |
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| Affiliation: | 1. Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany;2. Department of Chemistry, Nanoscience Center, University of Jyvaskyla, JYU, Finland |
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| Abstract: | A strategy to control the switch between a non‐cycloaddition reaction and a cycloaddition reaction of enals, using N‐heterocyclic carbene (NHC) catalyisis, has been developed. The new scalable protocol leads to γ‐amino‐acid esters bearing a tetrasubstituted stereocenter in good yields and high stereoselectivities by homo‐Mannich reactions of enals and isatin‐derived ketimines. By simply changing the N‐ketimine substituent to an ortho‐hydroxy phenyl group, the corresponding spirocyclic oxindolo‐γ‐lactams are obtained. |
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| Keywords: | asymmetric synthesis carbenes cycloaddition lactams oxindoles |
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