The reaction of 2-(tetrazol-5-yl)alkyl ketones and of 2-(tetrazol-5-yl)alkanoic acid derivatives with lead tetraacetate. A novel method of preparation of alk-2-ynyl ketones and alk-2-ynoic acid derivatives †
The majority of tetrazolylacetyl derivatives 2 and 7, when treated with leadtetraacetate in dry 1,4-dioxane at room or lower temperature, are oxidized with elimination of molecular nitrogen mainly to the corresponding alkynoyl derivatives 4 and 8, respectively. Vinylidenes (25) have been shown to be the intermediates of the reaction. The reaction does not take place when either the tetrazolyl group
A novel copper(II)-mediated route for the conversion of anilides into 3,3-disubstituted-oxindoles is described which proceeds via a formal CâH, ArâH coupling process.
Atom economical synthesis of oxindoles by metal-catalyzed intramolecular C–C bond formation under solvent-free and aerobic conditions
作者:Se In Son、Won Koo Lee、Jieun Choi、Hyun-Joon Ha
DOI:10.1039/c5gc00703h
日期:——
Diversely substituted oxindoles were obtained from atom economical direct C-C bondformation reactions of various substituted anilides and pyridinylamides with metal salts as catalysts including Cu2O, FeCl3, Fe2O3, TiO2, ZnO,...
Di-tert-butyl peroxide (DTBP) promoted dehydrogenative coupling: an expedient and metal-free synthesis of oxindoles via intramolecular C(sp<sup>2</sup>)–H and C(sp<sup>3</sup>)–H bond activation
作者:Biplab Mondal、Brindaban Roy
DOI:10.1039/c5ra09055e
日期:——
An efficient di-tert-butyl peroxide (DTBP) promoted synthesis of oxindole has been developed. This methodology involves C(sp3)–H and C(sp2)–H bond activation under metal-free conditions. This synthetic approach towards oxindole synthesis avoids bases and hazardous iodine reagents unlike other methodologies developed so far. This metal- and base-free protocol is operationally simple and ecofriendly
Intramolecular Dehydrogenative Coupling of sp<sup>2</sup> C–H and sp<sup>3</sup> C–H Bonds: An Expeditious Route to 2-Oxindoles
作者:Santanu Ghosh、Subhadip De、Badrinath N. Kakde、Subhajit Bhunia、Amit Adhikary、Alakesh Bisai
DOI:10.1021/ol302767w
日期:2012.12.7
An intramolecular-dehydrogenative-coupling (IDC) using "transition-metal-free" oxidation conditions has been achieved to synthesize a variety of 2-oxindoles bearing an all-carbon quaternary stereogenic center at the benzylic position. The methodology involves a one-pot C-alkylation of beta-N-arylamido esters (3, 6) with alkyl halides using potassium tert-butoxide concomitant with a dehydrogenative coupling. A radical-mediated pathway has been tentatively proposed for the oxidative process.