here a palladium(II)-catalyzed oxidative cyclization reaction of N-allylimines derived from methyl ketones, typically acetophenones, affording pyrrole derivatives at room temperature under oxygen atmosphere. The reaction likely proceeds through α-palladation of the imine followed by olefin migratory insertion and β-hydride elimination, thus representing a new example of aerobicdehydrogenative Heck cyclization
Carbon−Carbon Bond Formation and Pyrrole Synthesis via the [3,3] Sigmatropic Rearrangement of <i>O</i>-Vinyl Oxime Ethers
作者:Heng-Yen Wang、Daniel S. Mueller、Rachna M. Sachwani、Hannah N. Londino、Laura L. Anderson
DOI:10.1021/ol100659q
日期:2010.5.21
A new method for the synthesis of 2,4- and 2,3,4-substituted pyrroles in two or three steps from commercially available ketones and allyl hydroxylamine is described. An iridium-catalyzed isomerization reaction has been developed to convert O-allyl oximes to O-vinyl oximes, which undergo a facile [3,3] rearrangement to form 1,4-imino aldehyde Paal−Knorr intermediates that cyclize to afford the corresponding
Palladium-catalysed aerobic oxidative Heck-type alkenylation of Csp3–H for pyrrole synthesis
作者:Lingkui Meng、Kun Wu、Chao Liu、Aiwen Lei
DOI:10.1039/c3cc42307g
日期:——
The first palladium-catalysed aerobic oxidative intramolecular alkenylation of Csp(3)-H bonds was described. The reaction conditions were mild and molecular oxygen was used as the terminal oxidant. Kinetic studies showed that the Csp(3)-H metallation step was a slow step.
Pd(II)/Bu4NBr/DMSO Catalytic System for Practical Synthesis of Indoles and Pyrroles from Imines through Aerobic Dehydrogenative Cyclization
作者:Naohiko Yoshikai、Wei Tan、Xiaoya Hou
DOI:10.1055/s-0034-1379208
日期:——
scales (up to 55 mmol). N-Aryl- and N-allylimines derived typically from substituted acetophenones undergo palladium(II)-catalyzeddehydrogenativecyclization reactions in the presence of tetrabutylammonium bromide and molecular oxygen in DMSO to afford indole and pyrrole derivatives, respectively, in moderate to good yields. The reactions are operationally simple and can be readily performed on multigram