A Chiral 6-Membered <i>N</i>-Heterocyclic Carbene Copper(I) Complex That Induces High Stereoselectivity
作者:Jin Kyoon Park、Hershel H. Lackey、Matthew D. Rexford、Kirill Kovnir、Michael Shatruk、D. Tyler McQuade
DOI:10.1021/ol1021756
日期:2010.11.5
A chiral 6-membered annulated N-heterocyclic (6-NHC) copper complex that catalyzes β-borylations with high yield and enantioselectivity was developed. The chiral 6-NHC copper complex is easy to prepare on the gram scale and is very active, showing 10 000 turnovers at 0.01 mol % of catalyst without significant decrease of enantioselectivity and with useful reaction rates.
The highly efficient Ni-catalyzed asymmetric hydrogenation of β-boronic ester substituted-α,β-unsaturated carboxylic esters was successfully developed using (S,S)-Ph-BPE as the ligand. A series of chiral β-borylated carboxylic esters were obtained with high yields (94%–99% yields) and excellent enantioselectivities (89%–99% ee). The gram-scale asymmetric hydrogenation with a low catalyst loading (0
作者:Dimitri Hirsch-Weil、Khalil A. Abboud、Sukwon Hong
DOI:10.1039/c0cc02211j
日期:——
C
1-symmetric isoquinoline-based chiral diaminocarbene ligands (MIQ) have been developed to block three quadrants of the metal coordination sphere, complementing C2-symmetric biisoquinoline-based ligands (BIQ). MIQ-Cu complexes catalyzed conjugate borylation of various α,β-unsaturated amides in good yields (82–99%) and enantioselectivities (75–87% ee).
versions as electron-rich neutral stereodirecting ancillary ligands for enantioselective transformations. Herein we demonstrate that cyclic (alkyl)(amino)carbene (CAAC) ligands can also engage in asymmetric transformations, thereby expanding the toolbox of available chiral carbenes.
Enantioselective 1,1-Arylborylation of Alkenes: Merging Chiral Anion Phase Transfer with Pd Catalysis
作者:Hosea M. Nelson、Brett D. Williams、Javier Miró、F. Dean Toste
DOI:10.1021/jacs.5b00344
日期:2015.3.11
A palladium-catalyzed three-component coupling of α-olefins, aryldiazonium salts, and bis(pinacolato)diboron affords direct access to chiral benzylic boronic esters. This process is rendered highly enantioselective using an unprecedented example of cooperative chiralanionphasetransfer and transition-metal catalysis.