Su Jianke, Li Chengbo, Hu Xinyuan, Guo Yu, Song Qiuling
Institute of Next Generation Matter Transformation, College of Material Sciences Engineering at Huaqiao University, 668 Jimei Boulevard, Xiamen, Fujian, 361021, China.
School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China.
Angew Chem Int Ed Engl. 2022 Dec 23;61(52):e202212740. doi: 10.1002/anie.202212740. Epub 2022 Nov 24.
Transition-metal-catalyzed Suzuki-Miyaura coupling has significantly advanced C-C bond formation and has been well recognized in organic synthesis, pharmaceuticals, materials science and other fields. In this rapid development, cross coupling without transition metal catalyst is a big challenge in this field, and using widely existing tertiary amines as electrophiles to directly couple with boronic acids has great hurdles yet significant application prospects. Herein, we report an efficient and general deaminative arylation and alkenylation of tertiary amines (propargyl amines, allyl amines and 1H-indol-3-yl methane amines) with ary and alkenylboronic acids enabled by difluorocarbene under transition-metal-free conditions. Preliminary mechanism experiments suggest that in situ formed difluoromethyl quaternary amine salt, nitrogen ylide and tetracoordinate boron species are the key intermediates, the subsequent 1,2-metallate shift and protodeboronation complete the new coupling reaction.
过渡金属催化的铃木-宫浦偶联反应极大地推动了碳-碳键的形成，并在有机合成、制药、材料科学等领域得到了广泛认可。在这一快速发展过程中，无过渡金属催化剂的交叉偶联是该领域的一大挑战，而使用广泛存在的叔胺作为亲电试剂与硼酸直接偶联虽存在巨大障碍，但仍具有显著的应用前景。在此，我们报道了在无过渡金属条件下，二氟卡宾实现的叔胺（炔丙基胺、烯丙基胺和1H-吲哚-3-基甲胺）与芳基硼酸和烯基硼酸的高效通用脱氨基芳基化和烯基化反应。初步机理实验表明，原位形成的二氟甲基季铵盐、氮叶立德和四配位硼物种是关键中间体，随后的1,2-金属迁移和质子脱硼反应完成了新的偶联反应。
