Copper‐Catalyzed Cyclization/aza‐Claisen Rearrangement Cascade Initiated by Ketenimine Formation: An Efficient Stereocontrolled Synthesis of α‐Allyl Cyclic Amidines |
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Authors: | Dr Hua‐Dong Xu Zhi‐Hong Jia Ke Xu Mei Han Sai‐Nan Jiang Jing Cao Jia‐Cheng Wang Dr Mei‐Hua Shen |
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Institution: | School of Pharmaceutical Engineering and Life Science, Changzhou University, First Middle Gehu Road, Changzhou, Jiangsu Province, 213164 (China) |
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Abstract: | An efficient and convenient synthesis of α‐allyl cyclic amidines has been achieved by applying a novel cascade reaction. Copper(I)‐mediated in situ N‐sulfonyl ketenimine formation from the reaction of a terminal alkyne with sulfonyl azide is followed by an intramolecular nucleophilic attack on the central carbon atom by an allylic tertiary amine, and then an aza‐Claisen rearrangement takes place through a chair transition state to furnish the titled amidines with complete stereocontrol. |
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Keywords: | allylic compounds copper cyclization heterocycles rearrangements |
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