Phenols were vinylated at the ortho-position with ethyne in the presence of SnCl(4)-Bu(3)N reagent. The reaction was applicable to phenols possessing either electron-donating or electron-withdrawing groups. 2,6-Divinylphenols were synthesized under modified conditions. A reaction mechanism involving carbostannylation of alkynyltin and phenoxytin was discussed.
Electrooxidative Rhodium‐Catalyzed [5+2] Annulations via C−H/O−H Activations
作者:Yulei Wang、João C. A. Oliveira、Zhipeng Lin、Lutz Ackermann
DOI:10.1002/anie.202016895
日期:2021.3.15
five‐ and six‐membered heterocycles. In contrast, we herein describe the first electrochemical metal‐catalyzed [5+2] cycloadditions to assemble valuable seven‐membered benzoxepine skeletons by C−H/O−H activation. The efficient alkyne annulation featured ample substrate scope, using electricity as the only oxidant. Mechanistic studies provided strong support for a rhodium(III/I) regime, involving a
Catalytic Asymmetric [4+2] Cycloaddition of in Situ Generated <i>o</i>-Quinone Methide Imines with <i>o</i>-Hydroxystyrenes: Diastereo- and Enantioselective Construction of Tetrahydroquinoline Frameworks
作者:Lin-Zhi Li、Cong-Shuai Wang、Wei-Feng Guo、Guang-Jian Mei、Feng Shi
DOI:10.1021/acs.joc.7b02533
日期:2018.1.19
catalytic asymmetric [4+2] cycloaddition, the hydrogen-bonding interaction between chiral phosphoramide and two substrates was proposed to play a crucial role in controlling the enantioselectivity. This reaction not only provides a useful approach for constructing chiral tetrahydroquinoline frameworks, but also demonstrates the great practicability of ortho-quinone methide imines in catalytic asymmetric cycloadditions