Aerobic and Efficient Direct Arylation of Five-Membered Heteroarenes and Their Benzocondensed Derivatives with Aryl Bromides by Bulky 伪-Hydroxyimine Palladium Complexes

详细信息    查看全文

• 作者：Bao-Tian Luo ; Huan Liu ; Zhi-Jie Lin ; Jingxing Jiang ; Dong-Sheng Shen ; Rui-Zhi Liu ; Zhuofeng Ke ; Feng-Shou Liu
• 刊名：Organometallics
• 出版年：2015
• 出版时间：October 26, 2015
• 年：2015
• 卷：34
• 期：20
• 页码：4881-4894
• 全文大小：992K
• ISSN：1520-6041

文摘

In the present work, a series of 伪-hydroxyimine palladium complexes with bulky substituents (i.e., {[Ar-N鈺怌(R)鈥揅(R)₂鈥揙H]PdCl₂} (C1, R = Me, Ar = 2-diphenylmethyl-4,6-dimethylphenyl; C2, R = Me, Ar = 2,6-bis(diphenylmethyl)-4-methylphenyl; C3, R = Me, Ar = 2,6-bis(diphenylmethyl)-4-methyoxylphenyl; C4, R = Me, Ar = 2,6-bis(diphenylmethyl)-4-chlorophenyl; C5, R = Ph, Ar = 2,6-dimethylphenyl; C6, R = Ph, Ar = 2,6-diisopropylphenyl)) were synthesized and characterized. The structures of palladium complexes C1 and C2 were determined by X-ray diffraction. These bidentate N,O-palladium complexes were applied for direct arylation under aerobic conditions. The effects of the reaction conditions and ligand substitution on the catalytic activity were evaluated. Upon a low palladium loading of 0.5 mol %, the bulky palladium complex C6 was successfully used to catalyze the cross-coupling of a variety of five-membered heteroarenes and their benzo-condensed derivatives with (hetero)aryl bromides. The mechanistic investigation on the direct arylation supported the involvement of a Pd(0)/Pd(II) CMD process.