Department of Frontier Materials, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya, 466-8555 (Japan).
Rigaku Corporation, 3-9-12 Matsubara-cho, Akishima, Tokyo, 196-8666 (Japan).
Angew Chem Int Ed Engl. 2016 Jan 4;55(1):359-63. doi: 10.1002/anie.201508574. Epub 2015 Oct 21.
Enantioselective trichloromethylation of Morita-Baylis-Hillman (MBH)-type allylic fluorides with chloroform (HCCl3 ) under organocatalysis was achieved with high to excellent enantioselectivities. Silicon-assisted CF bond activation by a Ruppert-Prakash reagent and direct activation of HCCl3 by a carbanion exchange process with trifluoromethyl (CF3 ) carbanion generated in situ from the Ruppert-Prakash reagent realized the direct asymmetric trichloromethylation at a stereogenic allylic positon, without any help from transition metal catalysis, and under very mild conditions. Pre-activation of HCCl3 was not required. This method was extended to the direct enantioselective introduction of other C-H compounds such as alkyne, arene, indene, and FBSM without any pre-activation under a metal-free system.
在手性有机催化条件下，三氯甲基化试剂三氯甲烷（HCCl3 ）与 Morita-Baylis-Hillman (MBH)-型烯丙基氟化物反应，实现了高对映选择性的对映选择性三氯甲基化。硅辅助的 Ruppert-Prakash 试剂对 CF 键的活化，以及通过碳负离子交换过程直接活化 HCCl3 ，原位生成的三氟甲基（CF3 ）碳负离子来自 Ruppert-Prakash 试剂，实现了在立体中心烯丙位的直接不对称三氯甲基化，无需任何过渡金属催化，且反应条件非常温和。不需要预先活化 HCCl3 。该方法在无金属体系下，无需预先活化，就可以扩展到直接对映选择性地引入其他 C-H 化合物，如炔烃、芳烃、茚和 FBSM。
