Ru(II)‐Catalyzed Hydroarylation of in situ Generated 3,3,3‐Trifluoro‐1‐propyne by C−H Bond Activation: A Facile and Practical Access to β‐Trifluoromethylstyrenes
in situ generated 3,3,3-trifluoropropyne from the inexpensive 2-bromo-3,3,3-trifluoropropene was developed to access β-trifluoromethylstyrenes. A wide range of (hetero)arenes was functionalized leading selectively to the E-isomers. Detailed mechanistic studies and DFT calculations supported the involvement of an arene-free cyclometallated Ru(II) species and a bis-cyclometallated Ru complex as key intermediate
The development of a rational protocol to realize the complete regioselectivity and the capability to switch regioselectivity is an appealing yet challenging task. Herein, a regiodivergent C−H arylation of 2-pyridylthiophenes has been demonstrated via the choice of RuII and PdII catalysts. The reactions proceeded smoothly in a good regioselective manner to afford the corresponding C3- and C5-arylated
2-pyridylthiophenes with alkenes is realized. The alkenylation reactions proceeded smoothly in a highly regio- and stereo-selective manner to afford a broad range of C3- and C5-alkenylated products. Depending on the catalyst employed, the reactions involve two typical approaches: C3-alkenylation via chelation-assisted rhodation and C5-alkenylation via electrophilic palladation. This regiodivergent synthetic protocol
Palladium catalyzed ortho-C–H-benzoxylation of 2-arylpyridines using iodobenzene dibenzoates
作者:Qian Zhang、Ying Wang、Tingting Yang、Li Li、Dong Li
DOI:10.1016/j.tetlet.2015.09.097
日期:2015.10
A palladium-catalyzed ortho-C-H-benzoxylation of 2-arylpyridines using iodobenzene dibenzoates has been developed. The reaction employed the stable and easily accessible hypervalent iodine reagents as both benzoxylate source and oxidant which made the protocol simple and facile. It showed high regioselectivity and good functional group tolerance, and gave the mono-benzoxylation products in moderate to excellent yields. (C) 2015 Elsevier Ltd. All rights reserved.