Intramolecular dehydrogenative coupling of sp2 C-H and sp3 C-H bonds: an expeditious route to 2-oxindoles.

@article{Ghosh2012IntramolecularDC,
  title={Intramolecular dehydrogenative coupling of sp2 C-H and sp3 C-H bonds: an expeditious route to 2-oxindoles.},
  author={Santanu Ghosh and Subhadip De and Badrinath N. Kakde and Subhajit Bhunia and Amithava Adhikary and Alakesh Bisai},
  journal={Organic letters},
  year={2012},
  volume={14 23},
  pages={
          5864-7
        }
}
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 β-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. 
59 Citations
Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C–H and sp3 C–H bonds
The synthesis of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudo benzylic position has been achieved via a ‘transition-metal-free’ intramolecular dehydrogenativeExpand
Palladium-catalyzed oxidative direct C-H/C-H cross coupling of anilides with β-keto esters.
TLDR
This protocol provides facile access to α-aryl malonates and β-keto esters in good yields and regioselectivity. Expand
Synthesis of C3-Fluorinated Oxindoles through Reagent-Free Cross-Dehydrogenative Coupling.
TLDR
Under the unique and mild electrochemical conditions, the requisite oxidant and base are generated in a continuous fashion, allowing the formation of the base- and heat-sensitive 3-fluorooxindoles in high efficiency with broad substrate scope. Expand
Iodine-Catalyzed Direct Olefination of 2-Oxindoles and Alkenes via Cross-Dehydrogenative Coupling (CDC) in Air.
TLDR
A direct intermolecular olefination of sp(3) C-H bond between 2-oxindoles and simple alkenes via a Cross-Dehydrogenative Coupling (CDC) strategy has been developed and the transformation is proposed to proceed via a radical process. Expand
DDQ-mediated direct intramolecular-dehydrogenative-coupling (IDC): expeditious approach to the tetracyclic core of ergot alkaloids.
TLDR
An efficient route to 2-oxindoles bearing an all-carbon quaternary center at the pseudobenzylic position has been developed via a DDQ-mediated Intramolecular-Dehydrogenative-Coupling (IDC), which provides a two-step entry to the ergoline structure of ergot alkaloids. Expand
Electrochemical dehydrogenative cyclization of 1,3-dicarbonyl compounds.
TLDR
The intramolecular C(sp3)-H/C(sp2)-H cross-coupling of 1,3-dicarbonyl compounds has been achieved through Cp2Fe-catalyzed electrochemical oxidation through selective activation of the acidic α-C-H bond of the 1, 3-divel moiety to generate a carbon-centered radical. Expand
Highly chemoselective synthesis of dimeric 2-oxindoles with a C-3/C-5' linkage via Friedel-Crafts alkylations of 2-oxindoles with 3-hydroxy-2-oxindoles.
TLDR
The Friedel-Crafts reaction afforded a variety of dimeric 2-oxindoles with a C-3/C-5' linkage having an all-carbon quaternary center at the pseudobenzylic position in high yields. Expand
Metal-free synthesis of 2-oxindoles via PhI(OAc)2-mediated oxidative C–C bond formation.
TLDR
This metal-free method, shown to provide direct access to an important oxindole intermediate, could be applied to the total synthesis of naturally occurring horsfiline. Expand
Di-tert-butyl peroxide (DTBP) promoted dehydrogenative coupling: an expedient and metal-free synthesis of oxindoles via intramolecular C(sp2)–H and C(sp3)–H bond activation
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. ThisExpand
Oxidative cyanation of 2-oxindoles: formal total synthesis of (±)-gliocladin C.
Efficient oxidative direct cyanations of 3-alkyl/aryl 2-oxindoles using Cyano-1,2-BenziodoXol-3(1H)-one (CBX) (2a) have been reported under 'transition metal-free' conditions to synthesize a wideExpand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 63 REFERENCES
Oxindole synthesis by direct coupling of C(sp2)-H and C(sp3)-H centers.
An sp(2)/sp(3) get-together: A novel and efficient method can be used to synthesize 3,3-disubstitued oxindoles by the direct intramolecular oxidative coupling of an aryl C(sp(2))-H and a C(sp(3))-HExpand
First C-H activation route to oxindoles using copper catalysis.
TLDR
The preparation of 3,3-disubstituted oxindoles by a formal C-H, Ar-H coupling of anilides is described and a key intermediate for the total synthesis of the anticancer, analgesic oxindole alkaloid Horsfiline is also described. Expand
Cu-catalyzed cross-dehydrogenative coupling: a versatile strategy for C-C bond formations via the oxidative activation of sp(3) C-H bonds.
  • Zhiping Li, D. S. Bohle, C. Li
  • Medicine, Chemistry
  • Proceedings of the National Academy of Sciences of the United States of America
  • 2006
TLDR
Various sp, sp(2), and sp(3) C-H bonds of pronucleophiles were used in the Cu-catalyzed CDC reactions and the mechanisms of the CDC reactions are discussed. Expand
Lewis acid-catalyzed Friedel-Crafts alkylations of 3-hydroxy-2-oxindole: an efficient approach to the core structure of azonazine.
TLDR
A Lewis acid catalyzed Friedel-Crafts reaction of electron rich aromatics with 3-alkyl-3-hydroxy-2-oxindole with a straightforward access to the core of azonazine sharing an all-carbon quaternary stereocenter at the tetracyclic ring junction. Expand
Recent advances in the transition metal-catalyzed twofold oxidative C-H bond activation strategy for C-C and C-N bond formation.
TLDR
This critical review covers the recent progresses on the regioselective dehydrogenative direct coupling reaction of heteroarenes, including arylation, olefination, alkynylation, and amination/amidation mainly utilizing transition metal catalysts. Expand
Asymmetric Oxidative Dimerization of the Enolates of N-[Bis(methylthio)methylene]- and N-(Diphenylmethylene)glycine Esters.
TLDR
Under suitable conditions, high yields and diastereomeric excesses in favor of the threo derivatives 3-I, which have C(2) symmetry, were obtained and in the presence of 8-phenylmenthol as chiral auxiliary (2S, 3S)-3-aminoaspartic acid 5-I was synthesized. Expand
Phenyliodine bis(trifluoroacetate)-mediated oxidative C-C bond formation: synthesis of 3-hydroxy-2-oxindoles and spirooxindoles from anilides.
The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of anilides 1 (E = CO(2)Et) in CF(3)CH(2)OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with variousExpand
Metal-free intermolecular oxidative C-N bond formation via tandem C-H and N-H bond functionalization.
TLDR
Mechanistic investigations indicate that the reaction proceeds via nucleophilic attack of the phthalimide on an aromatic radical cation, as opposed to the electrophilic aromatic amination that has been reported for other I(III) amination reactions. Expand
Aza-oxindole synthesis by oxidative coupling of C(sp2)-H and C(sp3)-H centers.
A Cu(II) mediated oxidative C(sp(2))-H and C(sp(3))-H coupling protocol gives access to aza-oxindoles in good to excellent yield in the presence of NaOtBu as base and toluene as solvent.
Cross-dehydrogenative coupling reactions of sp3-hybridized C-H bonds.
TLDR
In this chapter, recent developments in oxidative cross-coupling reactions will be presented with the focus on the functionalization of sp3 C-H bonds with other C- H bonds. Expand
...
1
2
3
4
5
...