Ligand-Free Iron-Catalyzed Carbon (sp<sup>2</sup>)–Carbon (sp<sup>2</sup>) Oxidative Homo-Coupling of Alkenyllithiums
作者:Zhuliang Zhong、Zhi-Yong Wang、Shao-Fei Ni、Li Dang、Hung Kay Lee、Xiao-Shui Peng、Henry N. C. Wong
DOI:10.1021/acs.orglett.8b03893
日期:2019.2.1
and hexa-substituted 1,3-butadienes. This one-pot procedure involves lithium–iodine exchange to generate the corresponding vinyllithium intermediates. A subsequent iron-catalyzed ligand-free oxidativehomo-coupling eventually led to the formation of 1,3-butadienes in acceptable to excellent isolated yields.
An efficient and facile method for the construction of tri- or tetrasubstituted exocyclic alkenes is achieved via a Cu(I)-catalytic system. This protocol exhibits mild conditions, low-cost catalyst, good functional group tolerance, and good yields. The selectivity toward tri- or tetrasubstituted alkenes can be delicately controlled by adjustment of base and solvent. A preliminary mechanism study manifested that the reaction undergoes a radical process, where B(2)pin(2) plays an indispensable role.
YEH, MING CHANG P.;KNOCHEL, PAUL, TETRAHEDRON LETT., 30,(1989) N6, C. 4799-4802