Asymmetric Remote meta-C–H Activation Controlled by a Chiral Ligand

Abstract

The use of a chiral ligand for stereocontrol has assisted the development of a number of asymmetric functionalization of proximal C–H bonds. Herein, we report a chiral ligand-controlled, asymmetric remote meta-C–H activation of arenes, leading to asymmetric C–H olefination and arylation of hydrocinnamic acid derivatives through desymmetrization with Ac-L-Phe-OH as the chiral ligand using a Pd(II) catalyst. The origins of the enantioselectivity were explained with density functional theory calculations. The larger distortion energy of the substrate part in the C–H bond activation transition structure S-TS1 is the major controlling factor that disfavors the formation of the S-enantiomer product.

Converting CO2 into Value‐Added Products by Cu2O‐Based Catalysts: From Photocatalysis, Electrocatalysis to Photoelectrocatalysis

“…[ 10 ] In particular, the O and C atoms in the CO 2 molecule can act as electron donors and acceptors to form a mixed coordination structure with the catalyst (Figure 2c). [ 10 ] Then, CO 2 can be converted into a series of value‐added products, such as carbon monoxide (CO), [ 59–63 ] formic acid (HCOOH), [ 64 ] formaldehyde (CH 2 O), methanol (CH 3 OH), [ 65–67 ] methane (CH 4 ), [ 68–71 ] ethylene (CH 2 CH 2 ) [ 72–75 ] and ethanol (CH 3 CH 2 OH), [ 76–79 ] through reduction reactions involving 2e − , 4e − , 6e − , 8e − or more electrons. The thermodynamic potentials corresponding to different CO 2 reduction products are listed in Table 1 when the pH of the aqueous solution is 7, the temperature is 25 °C, and the pressure is 1 atm.…”

Hollow Hierarchical Cu2O‐Derived Electrocatalysts Steering CO2 Reduction to Multi‐Carbon Chemicals at Low Overpotentials

“…For o‐Cu 2 O, the activation in 4 m NaCl exerts little effect on the structure to form o‐Cu/Cu 2 O (Figure 2F), similar to the reported results. [ 17 ] We further studied the h‐Cu 2 O activation under different NaCl concentrations and found that the interior of activated h‐Cu 2 O remains solid with a lower Cl − salinity (1, 0.5, and 0.1 m ) or without Cl − (e.g., 0.1 m KHCO 3 ) (Figure S16, Supporting Information). This phenomenon can be explained by the sluggish formation of pinholes either in diluted Cl − salinity or on the robust surface of regular o‐Cu 2 O, where the surface reduction becomes dominant.…”

Amino Acid-Derived Ionic Chiral Catalysts Enable Desymmetrizing Cross-Coupling to Remote Acyclic Quaternary Stereocenters

“…10 Yu and co-workers, 11 and Phipps and co-workers 12 accomplished enantioselective arene meta C−H functionalization to access enantioenriched (diarylmethyl)amines. 13 Employing enzymes and organocatalysts, Lewis and co-workers 14 and Yeung and coworkers 15 of tert-Bu-substituted diarylmethane derivatives. These elegant studies require judicious choices of benzylic substituents (e.g., tert-Bu group and protected amino groups) at trisubstituted carbons, which are pivotal to the long-range enantioinduction.…”

“…To date, desymmetrization of two enantiotopic arenes of a trisubstituted carbon through transformations at the distant meta -positionsmost relevant to the vectorial derivatizationhas been made possible by very few ingenious catalysts. , Miller and co-workers pioneered long-range asymmetric Ullmann coupling to establish tertiary stereocenters (Scheme B) . Yu and co-workers, and Phipps and co-workers accomplished enantioselective arene meta C–H functionalization to access enantioenriched (diarylmethyl)­amines . Employing enzymes and organocatalysts, Lewis and co-workers and Yeung and co-workers have achieved desymmetrizing halogenation reactions of tert -Bu-substituted diarylmethane derivatives.…”