24438-17-3Relevant academic research and scientific papers
Electrochemical Umpolung C-H Functionalization of Oxindoles
Maulide, Nuno,Pastor, Miryam,Vayer, Marie,Weinstabl, Harald
, (2022/01/12)
Herein, we present a general electrochemical method to access unsymmetrical 3,3-disubstituted oxindoles by direct C-H functionalization where the oxindole fragment behaves as an electrophile. This Umpolung approach does not rely on stoichiometric oxidants and proceeds under mild, environmentally benign conditions. Importantly, it enables the functionalization of these scaffolds through C-O, and by extension to C-C or even C-N bond formation.
Oxidative Fragmentations and Skeletal Rearrangements of Oxindole Derivatives
Klare, Hendrik F. T.,Goldberg, Alexander F. G.,Duquette, Douglas C.,Stoltz, Brian M.
, p. 988 - 991 (2017/03/14)
An oxidative sequence for the conversion of oxindoles to structurally distinct heterocyclic scaffolds and aniline derivatives is disclosed by the combination of a copper-catalyzed C-H peroxidation and subsequent base-mediated fragmentation reaction. In contrast to classic enzymatic (i.e., kynurenine pathway) and biomimetic methods (i.e., Witkop-Winterfeldt oxidation) for oxidative indole cleavage, this protocol allows for the incorporation of external nucleophiles. The new transformation displays broad functional group tolerance and is applicable to tryptophan derivatives, opening potential new avenues for postsynthetic modification of polypeptides, bioconjugation, and unnatural amino acid synthesis.
Rh-Catalyzed Domino Addition-Enolate Arylation: Generation of 3-Substituted Oxindoles via a Rh(lll) Intermediate
Jang, Young Jin,Yoon, Hyung,Lautens, Mark
, p. 3895 - 3897 (2015/08/18)
A Rh-catalyzed domino conjugate addition-arylation sequence via a Rh(III) intermediate is reported. This process involving a proposed intramolecular oxidative addition of a rhodium enolate was utilized to achieve the synthesis of 3-substituted oxindole derivatives in moderate to excellent yields.
Molybdenum-catalyzed asymmetric allylic alkylation of 3-alkyloxindoles: Reaction development and applications
Trost, Barry M.,Zhang, Yong
, p. 2916 - 2922 (2011/05/02)
We report a full account of our work towards the development of Mo-catalyzed asymmetric allylic alkylation reactions with 3-alkyloxindoles as nucleophiles. The reaction is complementary to the Pd-catalyzed reaction with regard to the scope of oxindole nucleophiles. A number of 3-alkyloxindoles were alkylated successfully under mild conditions to give products with excellent yields and good-to-excellent enantioselectivities. Applications of this method to the preparation of indoline alkaloids such as (-)-physostigmine, ent-(-)-debromoflustramine B, and the indolinoquinoline rings of communesin B are reported.
Enantioselective TADMAP-catalyzed carboxyl migration reactions for the synthesis of stereogenic quaternary carbon
Shaw, Scott A.,Aleman, Pedro,Christy, Justin,Kampf, Jeff W.,Va, Porino,Vedejs, Edwin
, p. 925 - 934 (2007/10/03)
The chiral, nucleophilic catalyst TADMAP [1, 3-(2,2,2-triphenyl-1- acetoxyethyl)-4-(dimethylamino)-pyridine] has been prepared from 3-lithio-4-(dimethylamino)pyridine (5) and triphenylacetaldehyde (3), followed by acylation and resolution. TADMAP catalyzes the carboxyl migration of oxazolyl, furanyl, and benzofuranyl enol carbonates with good to excellent levels of enantioselection. The oxazole reactions are especially efficient and are used to prepare chiral lactams (23) and lactones (30) containing a quaternary asymmetric carbon. TADMAP-catalyzed carboxyl migrations in the indole series are relatively slow and proceed with inconsistent enantioselectivity. Modeling studies (B3LYP/6-31G*) have been used in qualitative correlations of catalyst conformation, reactivity, and enantioselectivity.
A novel biotransformation of benzofurans and related compounds catalysed by a chloroperoxidase
Alvarez, Ricardo G.,Hunter, Iain S.,Suckling, Colin J.,Thomas, Michael,Vitinius, Ute
, p. 8581 - 8587 (2007/10/03)
The oxidation of 3-alkyl benzofurans, indoles, and a benzothiophene by the chloroperoxidase from Caldariomyces fumago has been investigated. Under conditions in which the catalase activity of chloroperoxidase was minimised in the presence of chloride and hydrogen peroxide, 3-methylbenzothiophene was oxidised at sulfur but the indoles (5-9) and benzofurans (1-4) gave 2,3-diols as initial products. In the case of N-unsubstituted indoles, these tautomerised to give the corresponding lactam. In contrast, the diols (predominantly trans) formed from the benzofurans were sufficiently stable for isolation and full characterisation. This novel reaction has the potential to be developed into a useful synthetic biotransformation.
Palladium-Catalyzed Inter- and Intramolecular α-Arylation of Amides. Application of Intramolecular Amide Arylation to the Synthesis of Oxindoles
Shaughnessy, Kevin H.,Hamann, Blake C.,Hartwig, John F.
, p. 6546 - 6553 (2007/10/03)
2A palladium-catalyzed α-arylation of amides is reported. Intermolecular arylation of N,N-dimethylamides and lactams occurs using aryl halides, silylamide base, and a palladium catalyst. Intramolecular arylation of N-(2-halophenyl)amides occurs using alkoxide base and a palladium catalyst. The palladium catalyst was formed in situ from Pd(dba)2 (dba = trans,trans-dibenzylidene acetone) and BINAP (2,2′-bis(diphenylphosphino)-1,1′-binaphthalene). Although the intermolecular arylation of amides is less general than that reported previously for ketones, unfunctionalized and electron-rich aryl halides gave α-arylamides in 48-75% yield and N-methyl-α-phenylpyrrolidinone in 49% yield. These reactions provided the highest yields yet reported for regioselective amide arylations. Intramolecular amide arylation of 2-bromoanilides gave oxindoles in 52-82% yield. Mono- and disubstituted acetanilides gave 1,3-di- and 1,3,3-trisubstituted oxindoles. The use of dioxane, rather than THF, solvent was important for some of the amide arylations.
Tandem Radical Translocation and Homolytic Aromatic Substitution: a Convenient and Efficient Route to Oxindoles
Beckwith, Athelstan L. J.,Storey, John M. D.
, p. 977 - 978 (2007/10/02)
Suitable o-bromo-N-methylanilides are efficiently converted into oxindoles by treatment with tributylstannane at 160 degC via tandem translocation of the initially formed aryl radical and intramolecular homolytic substitution.
A New and Practical Synthesis of Indolones
Boivin, Jean,Yousfi, Mohammed,Zard, Samir Z.
, p. 9553 - 9556 (2007/10/02)
A variety of indolones can be obtained from α-haloanilides through a radical cyclisation mediated by a combination of nickel powder and acetic acid.
Electrocatalytic Coupling of Aryl Halides with (1,2-Bis(di-2-propylphosphino)benzene)nickel(0)
Fox, Marye Anne,Chandler, Daniel A.,Lee, Changjin
, p. 3246 - 3255 (2007/10/02)
Dibromo- and dichloro(1,2-bis(di-2-propylphosphino)benzene)nickel(II) is compared with tetrakis(triphenylphosphino)nickel(II) as an electrocatalyst for the reductive coupling of aryl halides.In many of the reactions examined, dehalogenation of the substrate predominated over coupling; however, preparative yields of biphenyls as high as 96percent can be obtained with aryl chlorides and 2 mol percent of the title catalyst in polar, coordinating solvents.Experimental factors governing the efficiency of these reactions are discussed, and possible mechanisms for coupling and catalyst deactivation are considered.Much better selectivity for aryl chlorides is attained in electroreductive couplings catalyzed by the title compound, whereas electrocatalysis with (Ph3P)4NiCl2 allows for selective intra- and intermolecular coupling at aryl bromide and vinyl chloride sites.Modest yields of cyclization products can be attained with either electrocatalyst in the presence of appropriately functionalized aryl or vinyl halides.
