Copper-catalyzed asymmetric cyclization of alkenyl diynes: method development and new mechanistic insights |
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| Authors: | Xin-Qi Zhu Pan Hong Yan-Xin Zheng Ying-Ying Zhen Feng-Lin Hong Xin Lu Long-Wu Ye |
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| Institution: | State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 China.; State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 China |
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| Abstract: | Metal carbenes have proven to be one of the most important and useful intermediates in organic synthesis, but catalytic asymmetric reactions involving metal carbenes are still scarce and remain a challenge. Particularly, the mechanistic pathway and chiral induction model in these asymmetric transformations are far from clear. Described herein is a copper-catalyzed asymmetric cyclization of alkenyl diynes involving a vinylic C(sp2)–H functionalization, which constitutes the first asymmetric vinylic C(sp2)–H functionalization through cyclopentannulation. Significantly, based on extensive mechanistic studies including control experiments and theoretical calculations, a revised mechanism involving a novel type of endocyclic copper carbene via remote-stereocontrol is proposed, thus providing new mechanistic insight into the copper-catalyzed asymmetric diyne cyclization and representing a new chiral control pattern in asymmetric catalysis based on remote-stereocontrol and vinyl cations. This method enables the practical and atom-economical construction of an array of valuable chiral polycyclic-pyrroles in high yields and enantioselectivities.A copper-catalyzed asymmetric cyclization of alkenyl diynes involving a vinylic C(sp2)–H functionalization is reported, enabling the construction of various valuable chiral polycyclic-pyrroles in high yields and enantioselectivities. |
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