Scope and selectivity in palladium-catalyzed directed C–H bond halogenation reactions
作者:Dipannita Kalyani、Allison R. Dick、Waseem Q. Anani、Melanie S. Sanford
DOI:10.1016/j.tet.2006.06.075
日期:2006.12
Palladium-catalyzed ligand directed C–H activation/halogenation reactions have been extensively explored. Both the nature of the directing group and the substitution pattern on the arene ring of the substrate lead to different reactivity profiles, and often different and complementary products, in the presence and absence of the catalyst.
The Rh(I)-catalyzed direct reorganization of organic frameworks and group exchanges between carboxylic acids and aryl ketones was developed with the assistance of directinggroup. Biaryls, alkenylarenes, and alkylarenes were produced in high efficiency from aryl ketones and the corresponding carboxylic acids by releasing the other molecule of carboxylic acids and carbon monoxide. A wide range of functional
Co(III)-Catalyzed C–H Activation/Formal S<sub>N</sub>-Type Reactions: Selective and Efficient Cyanation, Halogenation, and Allylation
作者:Da-Gang Yu、Tobias Gensch、Francisco de Azambuja、Suhelen Vásquez-Céspedes、Frank Glorius
DOI:10.1021/ja511011m
日期:2014.12.24
The first cobalt-catalyzed cyanation, halogenation, and allylation via C-Hactivation have been realized. These formal SN-type reactions generate valuable (hetero)aryl/alkenyl nitriles, iodides, and bromides as well as allylated indoles using a bench-stable Co(III) catalyst. High regio- and mono-selectivity were achieved for these reactions. Additionally, allylation proceeded efficiently with a turnover
In this work, we report the first use of a salen-based hypercrosslinked polymer-supportedPdcatalyst to carry out C-H halogenation. This catalyst can effectively catalyze C-H bromination and chlorination even better than its homogeneous counterpart Pd(OAc)2. It also showed excellent reusability without loss of catalytic activity for ten cycles. A broad substrate scope was explored and moderate to
Boron‐Mediated Regioselective Aromatic C−H Functionalization via an Aryl BF
<sub>2</sub>
Complex
作者:Ganesh H. Shinde、Henrik Sundén
DOI:10.1002/chem.202203505
日期:2023.2.16
Regioselectivefunctionalization of 2-aryl-azaarenes N-heteroarenes and aryl aldehydes has been achieved. The reaction proceeds via a BBr3 promoted 5 and 6-membered boracycle that undergoes a ligand exchange promoted by Selectfluor to give a previously scarce aryl BF2 species. The aryl BF2 is a bench stable intermediate that can be used for the deborylative functionalization of the 2-aryl-azaarenes