Axially chiral P-N ligands for the copper catalyzed β-borylation of α,β-unsaturated esters
作者:William J. Fleming、Helge Müller-Bunz、Vanesa Lillo、Elena Fernández、Patrick J. Guiry
DOI:10.1039/b900741e
日期:——
The synthesis and resolution of a new axially chiral Quinazolinap ligand are reported. The application of this and other related P-N ligands to the copper catalyzed β-borylation of α,β-unsaturated esters resulted in conversions of up to 100% and ee values of up to 79%. A diastereomerically pure palladacycle of the new ligand was characterised by X-ray crystallography.
Six-membered N-Heterocyclic Carbene-based catalysts for asymmetric reactions
申请人:McQuade D. Tyler
公开号:US20110054170A1
公开(公告)日:2011-03-03
The present invention provides a catalyst complex or ligand, and compositions thereof, for use in a variety of organic reactions having high reactivity and enantioselectivity. The catalyst is a N-heterocyclic carbene having three fused rings with first and second rings being six-membered rings and the third being a five-membered ring. The first ring is fused to the second and has four substituents. The second ring has two nitrogens flanking a carbene atom with one nitrogen bound to a substituent. The carbene atom may optionally be bonded to a metal. The third ring is fused to the second ring and contains two nitrogens. The third ring of the catalyst has a double bond and two substituents on adjacent non-fused carbons. A non-fused nitrogen of the third ring is partially bonded to another substituent. Methods for the synthesis and use of the catalyst embodiments of the present invention are also provided.
Regio‐ and Diasteroselective
<scp>
<i>C</i>
‐Silylation
</scp>
of Enolate Enabled by a
<scp>β‐Boronyl</scp>
Group
作者:Yu Liu、Miao Zhan、Pengfei Li
DOI:10.1002/cjoc.202100792
日期:2022.5
Silyl enol ethers are often obtained when the lithiumenolates are trapped with chlorosilanes. Herein, we report a general method for the regio- and diasteroselective C-silylation of enolate enabled by the β-boronyl group. The formation of five-membered chelation intermediate is key to the C-selective silylation and anti-selectivity. The operationally simple protocol provides a general and predictable
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.