Direct Electrophilic C−H Alkynylation of Unprotected 2-Vinylanilines
作者:Lucien D. Caspers、Peter Finkbeiner、Boris J. Nachtsheim
DOI:10.1002/chem.201606026
日期:2017.2.24
Unprotected aromatic amines can be used as directing groups in metal‐catalyzed C−H alkynylations of alkenes. By using low amounts of an IrIII catalyst in combination with alkynylbenziodoxolones as electrophilic alkyne‐transfer reagents, highly desirable 1,3‐enynes were isolated in excellent yields of up to 98 % with Z stereoselectivity. A broad substrate scope as well as the high synthetic utility
NH<sub>2</sub>-Directed C–H Alkenylation of 2-Vinylanilines with Vinylbenziodoxolones
作者:Andreas Boelke、Lucien D. Caspers、Boris J. Nachtsheim
DOI:10.1021/acs.orglett.7b02630
日期:2017.10.6
directing-group-mediated C–H alkenylation with alkenyl-λ3-iodanes as electrophilic alkene-transfer reagents has been developed. The application of free aromatic amines as challenging but synthetically valuable directing groups in combination with an IrIII catalyst enabled the synthesis of highly desirable 1,3-dienes in excellent yields of up to 98% with high to perfect (Z,E) stereoselectivity. A broad substrate
oxindole synthesis bearing an all-carbon quaternary center, enabled by Pd-catalyzed intramolecular cyclization followed by multiple intermolecular Heck reactions of both easily accessible alkene-tethered carbamoyl chlorides and olefins. This protocol obviates the use of prefunctionalized olefinic reagents, exhibits excellent functional group tolerance, and features fascinating reactive versatility.
A readily accessible and bench-stable water-soluble hypervalent iodine(III) reagent (phenyliodonio)sulfamate (PISA) with an I–N bond was synthesized, and its structure was characterized by X-ray crystallography. With PISA, various indoles were synthesized via C–H amination of 2-alkenylanilines involving an aryl migration/intramolecular cyclization cascade with excellent regioselectivity in aqueous
Experimental and Computational Studies on Cp*<sup>Cy</sup>Rh(III)/KOPiv-Catalyzed Intramolecular Dehydrogenative Cross-Couplings for Building Eight-Membered Sultam/Lactam Frameworks
作者:Liping Li、Hui Gao、Ming Sun、Zhi Zhou、Wei Yi
DOI:10.1021/acs.orglett.0c01823
日期:2020.7.17
is an unusual Cp*CyRh(III)-catalyzed intramolecular site-specific aryl C–H annulation, a highly chemoselective protocol providing direct access to eight-membered sultams/lactams with broad substrate/functional group tolerance. Experimental and computational studies reveal that such a transformation involves a unique PivOH-assisted aryl C–H activation/alkene insertion/β-H elimination/hydrogen-transfer