Controllable Isomerization of Alkenes by Dual Visible‐Light‐Cobalt Catalysis
作者:Qing‐Yuan Meng、Tobias E. Schirmer、Kousuke Katou、Burkhard König
DOI:10.1002/anie.201900849
日期:2019.4.16
We report herein that thermodynamic and kineticisomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor–acceptor dye 4CzIPN accelerates the reaction
Tandem Reactions Involving 1-Silyl-3-Boryl-2-Alkenes. New Access to (<i>Z</i>)-1-Fluoro-1-Alkenes, Allyl Fluorides, and Diversely α-Substituted Allylboronates
The reactions of 1-silyl-3-boryl-2-alkenes with various electrophilic reagents (Selecffluor, N-halosuccinimides, benzhydryl, and propargylic alcohols In the presence of a Lewis acid, N-alkoxycarbonyliminium ion) have been investigated as new routes to alpha-substituted allylboronates. Further functional transformations, including allylboration, Suzuki coupling, protodeboronation, and cycloisomerization, have been carried out to illustrate the synthetic potential of these gamma-borylallylsilanes.