Copper-Catalyzed Radical Allene C(sp2)-H Cyanation
Youhao Wei1, Zheng Wang1, Kaifeng Wang1, Jiang-Kai Qiu2*(邱江凯), Zhaoshan Wang1,Haotian Li1, Xiu Duan1,2, Kai Guo2, Xiaoguang Bao1*(鲍晓光), Xinxin Wu1*(吴新鑫)
1Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu 215123, China
2College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
Angew. Chem. Int. Ed. 2023, e202317132
Abstract：While the hydrogen atom abstraction (HAA) from C(sp3)-H bond has been well explored, the radical-mediated chemo- and regioselective functionalization of allenic C(sp2)-H bond via direct HAA from C(sp2)-H bond of allene remains an unsolved challenge in synthetic chemistry. This is primarily due to inherent challenges with addition of radical intermediates to allenes, regioselectivity of HAA process, instability of allenyl radical toward propargyl radical et al. Herein, we report a copper catalyzed allenic C(sp2)-H cyanation of an array of triand di-substituted allenes with exceptional site-selectivity, while mono-substituted allene was successfully cyanated, albeit with a low yield. In the developed strategy, steric N-fluoro-N-alkylsulfonamide, serving as precursor of hydrogen atom abstractor, plays a crucial role in achieving the desired regioselectivity and avoiding addition of N centered radical to allene.
链接：//onlinelibrary.wiley.com/doi/10.1002/anie.202317132
