Engaging Allene‐Derived Zwitterions in an Unprecedented Mode of Asymmetric [3+2]‐Annulation Reaction |
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| Authors: | Dr Muthukumar G Sankar Dr Miguel Garcia‐Castro Christopher Golz Prof?Dr Carsten Strohmann Dr Kamal Kumar |
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| Institution: | 1. http://www.mpi‐dortmund.mpg.de/74401/Kumar
0000-0002-8869-9041
Max-Planck-Institut für Molekulare Physiologie, Abteilung Chemische Biologie, Dortmund, Germany;2. Max-Planck-Institut für Molekulare Physiologie, Abteilung Chemische Biologie, Dortmund, Germany;3. Fakult?t Chemie und Chemische Biologie, Technische Universit?t Dortmund, Dortmund, Germany |
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| Abstract: | Catalytic addition of chiral phosphine, that is, (R)‐ or (S)‐SITCP, to an α‐substituted allene ester generated a zwitterionic dipole. Under optimized reaction conditions, this dipole could engage isatine‐derived N‐Boc‐ketimines in a novel mode of 3+2] annulation reaction. Pyrrolinyl spirooxindoles are thus afforded in high yields and with excellent enantioselectivities. The unprecedented annulation reaction successfully facilitated the construction of sp3‐rich and highly substituted 3,2′‐pyrrolidinyl spirooxindoles supporting many chiral centers. |
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| Keywords: | allenes asymmetric synthesis phosphine catalysis spirooxindoles zwitterions |
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