Highly Asymmetric Intramolecular Cyclopropanation of Acceptor-Substituted Diazoacetates by Co(II)-Based Metalloradical Catalysis: Iterative Approach for Development of New-Generation Catalysts

作者：Xu Xue; Lu Hongjian; Ruppel Joshua V; Cui Xin; de Mesa Silke Lopez; Wojtas Lukasz; Zhang X Peter^*

来源：Journal of the American Chemical Society, 2011, 133(39): 15292-15295.

DOI：10.1021/ja2062506

3,5-Di(t)Bu-QingPhyrin, a new D-2-symmetric chiral porphyrin derived from a chiral cyclopropanecarboxamide containing two contiguous stereocenters, has been developed using an iterative approach based on Co(II)-catalyzed asymmetric cydopropanation of alkenes. The Co (II) complex of 3,5-DitBu-QingPhyrin, [Co (P2)], has proved to be a general and effective catalyst for asymmetric intramolecular cydopropanation of various allylic diazoacetates (especially including those with a-acceptor substituents) in high yields with excellent stereoselectivities. The [Co(P2)]-based intramolecular metalloradical cyclopropanation provides convenient access to densely functionalized 3-oxabicyclo [3.1.0]hexan-2-one derivatives bearing three contiguous quaternary and tertiary chiral centers with high enantiomeric purity.

• 出版日期2011-10-5