A nickel-catalyzed heteroannulation has been developed where o-haloanilines react with alkynes to afford 2,3-disubstituted indoles. IPr (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) was found to be an effective ligand for the reaction.
Palladium-catalyzed annulation of internal alkynes in aqueous medium
作者:Wei Jie Ang、Chih-Hsuan Tai、Lee-Chiang Lo、Yulin Lam
DOI:10.1039/c3ra46010j
日期:——
To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for carbo- and heteroannulation of internal alkynes with functionalized aryl halides in aqueous medium. A uniform reaction condition for these annulation reactions was also developed.
Synthesis of Fluoren-9-ones by the Palladium-Catalyzed Cyclocarbonylation of <i>o</i>-Halobiaryls
作者:Marino A. Campo、Richard C. Larock
DOI:10.1021/jo020140m
日期:2002.8.1
The synthesis of various substituted fluoren-9-ones has been accomplished by the palladium-catalyzed cyclocarbonylation of o-halobiaryls. The cyclocarbonylation of 4'-substituted 2-iodobiphenyls produces very high yields of 2-substituted fluoren-9-ones bearing either electron-donating or electron-withdrawing substituents. 3'-Substituted 2-iodobiphenyls afford 3-substituted fluoren-9-ones in excellent
Palladium/NBE-Catalyzed Regioselective C–H Silylation: Access to Divergent Silicon-Containing Indoles
作者:Wenguang Li、Man Cao、Chunyan Zhang、Shukui Shi、Juan Liu、Wentao Li、Xu Zhang、Yongqi Yu、Ting Li
DOI:10.1021/acs.orglett.3c04109
日期:2024.2.16
A palladium/norbornene (NBE)-catalyzed regioselective C–H silylation of free NH-indoles is reported. This protocol uses Pd(OAc)2 as the catalyst and Cu(OAc)2 as the oxidant, and the reaction relies on the control of NBE as a switch. The reaction tolerates various functional groups, and a series of silicon-containing indoles were directly synthesized in 30%–94% yields.
Synthesis of 2,3-Disubstituted Indoles via Palladium-Catalyzed Annulation of Internal Alkynes
作者:R. C. Larock、E. K. Yum、M. D. Refvik
DOI:10.1021/jo9803277
日期:1998.10.1
The palladium-catalyzed coupling of 2-iodoaniline and the corresponding N-methyl, -acetyl, and -tosyl derivatives with a wide variety of internal alkynes provides 2,3-disubstituted indoles in good-to-excellent yields. The best results are obtained by employing an excess of the alkyne and a sodium or potassium acetate or carbonate base plus 1 equiv of either LiCl or n-Bu4NCl, occasionally adding 5 mol % PPh3. The yields with LiCl appear to be higher and more reproducible than those obtained with n-Bu4NCl. The process is quite general as far as the types of substituents which can be accommodated on the nitrogen of the aniline and the two ends of the alkyne triple bond. The reaction is quite regioselective, placing the aryl group of the aniline on the less sterically hindered end of the triple bond and the nitrogen moiety on the more sterically hindered end. This methodology readily affords 2-silylindoles, which can be easily protodesilylated, halogenated, or reacted with alkenes and Pd(OAc)(2) to produce 3-substituted indoles, 2-haloindoles, or 2-(1-alkenyl)indoles, respectively. The presence of alcohol groups in the alkyne seems to have a particularly strong directing effect, perhaps due to coordination with palladium. This catalytic process apparently involves arylpalladium formation, regioselective addition to the C-C triple bond of the alkyne, and subsequent intramolecular palladium displacement.