Palladium-Catalyzed Cycloisomerization of 2-Ethynylbiaryls to 9-Methylidene Fluorenes
作者:Hongyu Guo、Sheng Zhang、Xiujuan Feng、Xiaoqiang Yu、Yoshinori Yamamoto、Ming Bao
DOI:10.1021/acs.orglett.2c00534
日期:2022.4.15
presence of weak acid at low temperature to afford 9-methylidene fluorenes in satisfactory to high yields. This new type of cycloisomerization of 2-ethynylbiaryls is operationally simple and scalable and exhibits high functional-group tolerance. Various synthetically useful functional groups, such as halogen atoms, as well as formyl, acetyl, methoxycarbonyl, cyano, and nitro groups, remain intact during
首次描述了钯催化的 2-乙炔基联芳基环异构化为 9-亚甲基芴。2-乙炔基联芳基的环化异构化在弱酸存在下在低温下顺利进行,以令人满意的高收率得到9-亚甲基芴。这种新型的 2-乙炔基联芳基环异构化操作简单且可扩展,并表现出高官能团耐受性。各种合成有用的官能团,如卤素原子,以及甲酰基、乙酰基、甲氧羰基、氰基和硝基,在 2-乙炔基联芳基的环异构化过程中保持完整。