cross‐dehydrogenative coupling of arene carboxylicacids with olefins is reported with ruthenium(II) catalyst employing air and water as green oxidant and solvent, respectively. It offers a robust synthesis of valuable phthalide molecules. A one‐pot sequential strategy is also disclosed to access Heck‐type products that are apparently difficult to make directly from arene carboxylicacids.
Ruthenium(<scp>ii</scp>)-catalyzed C–H functionalizations on benzoic acids with aryl, alkenyl and alkynyl halides by weak-O-coordination
作者:Ruhuai Mei、Cuiju Zhu、Lutz Ackermann
DOI:10.1039/c6cc07773k
日期:——
C-H arylations of weakly coordinating benzoic acids were achieved by versatile ruthenium(II) catalysis with ample substrate scope. Thus, user-friendly ruthenium(II) biscarboxylate complexes modified with tricyclohexylphosphine enabled C-H functionalizations with aryl...
The ortho-olefination of benzoic acids can be achieved effectively through rhodium-catalyzed oxidative coupling with alkenes. The carboxylic group is readily removable to allow ortho-olefination/decarboxylation in one pot. alpha,beta-Unsaturated carboxylic acids such as methacrylic acid also undergo the olefination at the beta-position. Under the rhodium catalysis, the cine-olefination of heteroarene carboxylic acids such as thiophene-2-carboxylic acid proceeds smoothly accompanied by decarboxylation to selectively produce the corresponding vinylheteroarene derivatives.
Ru-Catalyzed (<i>E</i>)-Specific <i>ortho</i>-C–H Alkenylation of Arenecarboxylic Acids by Coupling with Alkenyl Bromides
作者:Zhiyong Hu、Florian Belitz、Guodong Zhang、Florian Papp、Lukas J. Gooßen
DOI:10.1021/acs.orglett.1c00956
日期:2021.5.7
alkenyl bromides, (E)-configured vinyl arenes or dienes are formed exclusively. Mechanistic studies show that this selectivity is achieved because the (E)-configured alkenyl bromides undergo a smooth coupling, whereas the (Z)-isomers are rapidly eliminated with the formation of alkynes.
We developed a novel thiourea Lewis-base catalyst with phenol moieties for the enantioselective 5-exo-bromolactonization of stilbenecarboxylic acids to afford chiral 3-substituted phthalides. The phenol moieties are crucial for the enantio- and regio-selectivity.