Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
J Am Chem Soc. 2012 Oct 10;134(40):16496-9. doi: 10.1021/ja307371w. Epub 2012 Sep 28.
Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (nonoxidative) Heck reaction between a vinyl bromide and an alkene. DFT computational studies reveal that steric effects of the 2,9-dimethylphenanthroline ligand promote C-C bond formation at the internal position of the alkene.
钯催化的乙烯基硼酸和非电子偏向性的烷基烯烃的有氧氧化偶联反应为 1,3-二取代共轭二烯提供了区域选择性的合成途径。通过使用 2,9-二甲基菲咯啉作为配体，可以实现催化剂控制的区域选择性。观察到的区域选择性与传统（非氧化） Heck 反应中乙烯基溴化物和烯烃之间的反应相反。DFT 计算研究表明，2,9-二甲基菲咯啉配体的空间位阻效应促进了烯烃内部位置的 C-C 键形成。
