Borane‐Catalyzed Chemoselective and Enantioselective Reduction of 2‐Vinyl‐Substituted Pyridines
作者:Jun‐Jie Tian、Zhao‐Ying Yang、Xin‐Shen Liang、Ning Liu、Chen‐Yu Hu、Xian‐Shuang Tu、Xiang Li、Xiao‐Chen Wang
DOI:10.1002/anie.202007352
日期:2020.10.12
Herein, we report that highly chemoselective and enantioselectivereduction of 2‐vinyl‐substituted pyridines has been achieved for the first time. The reaction, which uses chiral spiro‐bicyclic bisboranes as catalysts and HBpin and an acidic amide as reducing reagents, proceeds through a cascade process involving 1,4‐hydroboration followed by transfer hydrogenation of a dihydropyridine intermediate
been reported that fulfill this objective. All the reported examples are homogeneous catalysts with special ligands requiring the usage of bases. This study describes the heterogeneously catalyzed dehydrogenative borylation by supportedcopper hydroxide catalysts (Cu(OH)x/support). In the presence of Cu(OH)x/support and suitable ketones, the dehydrogenative borylation of styrenes with bis(pinacolato)diboron
Dehydrogenative Borylation and Silylation of Styrenes Catalyzed by Copper-Carbenes
作者:Thomas J. Mazzacano、Neal P. Mankad
DOI:10.1021/acscatal.6b02594
日期:2017.1.6
Readily available copper precatalysts, (NHC)CuOtBu (NHC = N-heterocyclic carbene), catalyze dehydrogenative borylation and silylation of styrenes with moderate to high yields, using ketone additives as sacrificial oxidants. This method provides access to trisubstituted vinylboronates and vinylsilanes without requiring noble metal catalysis.
Rhodium-catalyzed dehydrogenative borylation of cyclic alkenes
作者:Azusa Kondoh、Timothy F. Jamison
DOI:10.1039/b921387b
日期:——
A rhodium-catalyzed dehydrogenative borylation of cyclic alkenes is described. This reaction provides direct access to cyclic 1-alkenylboronic acid pinacol esters, useful intermediates in organic synthesis. Suzuki–Miyaura cross-coupling applications are also presented.