Palladium‐Titanium Relay Catalysis Enables Switch from Alkoxide‐π‐Allyl to Dienolate Reactivity for Spiro‐Heterocycle Synthesis |
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| Authors: | Dr. Li‐Cheng Yang Zher Yin Tan Dr. Zi‐Qiang Rong Ruoyang Liu Ya‐Nong Wang Prof. Yu Zhao |
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| Affiliation: | 1. http://zhaoyugroup.sg;2. Department of Chemistry, National University of Singapore, Singapore, Singapore |
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| Abstract: | Reported herein is the divergent syntheses of [5,5] and [6,5] spiro‐heterocycles under Lewis‐acid‐assisted palladium catalysis. In particular, an unprecedented switch from alkoxide‐π‐allyl to dienolate reactivity was achieved by the use of palladium‐titanium relay catalysis, and represents umpolung reactivity of vinylethylene carbonates. This method uses a simple procedure and commercially available catalysts, and delivers both classes of spiro‐heterocycles, bearing three contiguous stereocenters, in high yield and uniformly excellent diastereoselectivity. |
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| Keywords: | cycloaddition palladium relay catalysis spiro compounds umpolung |
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