Chao Deng, Hua-Kui Liu, Zhong-Bo Zheng, Lijia Wang,* Xiang Yu, Weihua Zhang,* Yong Tang. Copper-Catalyzed Enantioselective Cyclopropanation of Internal Olefins with Diazomalonates.
Org. Lett. 2017, 19, 5717–5719. (IF2016= 6.579)
The first enantioselective copper catalyzed cyclopropanation of internal olefins with diazomalonates is reported. This process provides a new method for the synthesis of chiral 1,1-cyclopropane diesters. With a chiral bi-side arm bisoxazoline–copper(I) complex, the reaction performed well over a series of substrates, giving the desired products in good yields (up to 95%) and excellent enantioselectivities (90–95% ee).