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Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Hydrazine-mediated carbonyl-alkyne/allene reductive olefination
Linjun Qi1, Wencan Wang2, Lijin Zhou3
1School of Pharmaceutical and Chemical Engineering, Zhejiang Key Laboratory of New Drug Development for Central Nervous System Diseases, Taizhou University, Taizhou, Zhejiang, China. qilinjun@tzc.edu.cn.
Abstract:
Cycloolefin is a privileged motif with significant implications across multiple disciplines. While cycloolefination represents the most unified disconnection strategy, the corresponding approaches are notably scarce. Here we report a hydrazine-mediated carbonyl-alkyne reductive olefination (CARO), offering a minimalist approach to structurally complex cycloolefins. This CARO protocol is also applicable to carbonyl-allene and lactol-alkyne analogues. Experimental studies and DFT calculations suggest that the CARO follows a domino mechanism involving carbonyl-hydrazine condensation, ene reaction of free hydrazone, and denitrogenative retro-ene reaction. Its synthetic potential is demonstrated by the facile preparation of several medicinally important molecules, deuterated compounds and valuable chirons. This study provides a fundamentally distinct, operationally simple and cost-effective strategy for accessing complex architectures, appealing to both organic and medicinal chemists.
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