Wang Yunpeng, Lv Jiaying, Hua Ruimao
Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, China.
J Org Chem. 2024 Jun 21;89(12):8851-8860. doi: 10.1021/acs.joc.4c00733. Epub 2024 Jun 5.
A CuBr-catalyzed cross-coupling reaction of propargyl bromides with terminal alkynes for the synthesis of 1, n-diynes was investigated. In ,-dimethylacetamide (DMAc), the cross-coupling reactions of 3-bromo-1-arylpropynes, 3-bromo-1-phenyl-butyne/pentyne with aromatic terminal alkynes in the presence of CuBr and KPO under nitrogen at 40 °C occur to give 1, 5-diaryl-1, 4-diynes having 3-CH/3-CHMe/3-CHEt/3-CHPr moieties with high chemoselectivity. Under similar reaction conditions, either the reactions of 3-bromo-1-arylpropynes with aliphatic terminal alkynes or the reactions of 3-bromo-1-alkylpropynes with aromatic terminal alkynes afforded the unexpected unsymmetric 1, 4-disubstituted 1, 3-diynes through one of the alkynyl group shifts to the side conjugating with the aryl group; in these cases, 1, 5-disubstituted 1, 4-diynes could not be obtained at all. In addition, when 3-bromo-1-phenyl-butynes react with aliphatic terminal alkynes bearing a distal phenyl group, the formed 1, 4-diynes are expected not to undergo the alkynyl group shift due to the methyl group at 3-position to form 1, 3-diynes; however, 1, 4-diynes could not be obtained either, and the 1, 5-, 1, 6-, and 1, 7-diynes, by an unprecedented remote alkynyl shift to the side conjugating with the aryl group, were isolated from the reaction mixtures in good yields.
研究了溴化亚铜催化的炔丙基溴与末端炔烃的交叉偶联反应以合成1,n -二炔。在N,N -二甲基乙酰胺（DMAc）中，3 -溴 - 1 -芳基丙炔、3 -溴 - 1 -苯基 -丁炔/戊炔与芳香族末端炔烃在溴化亚铜和磷酸钾存在下于氮气氛围40℃发生交叉偶联反应，以高化学选择性得到具有3 - CH/3 - CHMe/3 - CHEt/3 - CHPr基团的1,5 -二芳基 - 1,4 -二炔。在类似反应条件下，3 -溴 - 1 -芳基丙炔与脂肪族末端炔烃的反应或3 -溴 - 1 -烷基丙炔与芳香族末端炔烃的反应通过炔基向与芳基共轭的一侧迁移，意外地得到了不对称的1,4 -二取代 - 1,3 -二炔；在这些情况下，根本无法得到1,5 -二取代 - 1,4 -二炔。此外，当3 -溴 - 1 -苯基 -丁炔与带有远端苯基的脂肪族末端炔烃反应时，由于3 -位的甲基，预期形成的1,4 -二炔不会发生炔基迁移以形成1,3 -二炔；然而，也无法得到1,4 -二炔，并且通过前所未有的远程炔基向与芳基共轭的一侧迁移，从反应混合物中以良好产率分离出了1,5 -、1,6 -和1,7 -二炔。
