Compounds and Methods for Catalytic Directed ortho Substitution of Aromatic Amides and Esters
申请人:Zhao Yigang
公开号:US20120302752A1
公开(公告)日:2012-11-29
Methods are described for efficient and regioselective reactions that are Ru-catalyzed and either (i) amide-directed C—H, C—N, C—O activation/C—C bond forming reactions, (ii) ester-directed C—O and C—N activation/C—C bond forming reactions, or (iii) amide-directed C—O activation/hydrodemethoxylation reactions. All of these reactions of directed C—H, C—N, C—O activation/coupling reactions establish a catalytic base-free DoM-cross coupling process at non-cryogenic temperature. High regioselectivity, yields, operational simplicity, low cost, and convenient scale-up make these reactions suitable for industrial applications. Many previously unknown amide-substituted or ester-substituted aryl and heteroaryl compounds are presented with synthetic details also provided.
Ortho-substituted benzoic acids efficiently undergo precisely ordered ortho-olefination/decarboxylation upon treatment with styrenes in the presence of a rhodium catalyst and silversalt oxidant to afford the corresponding meta-substituted stilbene derivatives. The selective syntheses of 1,3- and 1,4-distyrylbenzenes have also been realized through the reactions of simple benzoic acid and phthalic
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.