Solid-phase synthesis of indolines via palladium-catalyzed cyclization

The solid-phase synthesis of indolines from resin-bound 2-bromophenylacetylated amino acids is described. The exhaustive reduction of solid-support bound amides with borane afforded the requisite secondary amines that, following the palladium-catalyzed intramolecular cyclization and cleavage, provided the corresponding disubstituted indolines.     

Alkoxyamine-mediated radical synthesis of indolinones and indolines

Thermolysis of alpha-alkoxyamino propionanilides produces indolinones, whereas thermal reaction of N-allylaniline derivatives with various Tordo-type alkoxyamines results in formation of indolines in the radical regime. [reaction: see text]     

Regioselective electrophilic trifluoromethylation of indolines, oxindoles and indoles in superacid

Treatment of indolines and N-acylindoles with HF/SbF₅/CCl₄ yields 6-trifluoro derivatives (indole numbering) whereas indoles and oxindoles give the 5-trifluoro derivatives in good yield.     

Heteroatom directed photoarylation synthesis of functionalized indolines

The photochemical syntheses of indolines 25-28 are described.     

Synthesis of indolines from N-allylarylamines

A novel method of synthesis of nitrogen heterocycles is described. The acidic rearrangement of N-allylanilines gives 2-allylanilines which lead to indolines by photocyclization.     

One-pot synthesis of highly substituted indolines

A general and convenient one-pot synthesis of highly substituted indolines from arylhydrazines and aldehydes is reported. This synthesis allows introduction of substitution at essentially all positions of the indoline nucleus to achieve significant diversity in this biologically important template.     

Une nouvelle methoxylation d'hydroperoxy-3 indolines issues de la photo-oxygenation d'indoles en milieu reducteur

3-Hydroperoxy-1,3,6-trimethyl-2-phenyl indolines coming from the sensitized photooxygenation of the indoles in presence of KBH₄ rearrange partially in basic methanol into the corresponding 3-hydroxy-6-methoxymethyL indolines.     

Strategies for the synthesis of 2-substituted indoles and indolines starting from acyclic alpha-phosphoryloxy enecarbamates

Strategies have been developed for the synthesis of 2-substituted indoles and indolines starting from acyclic alpha-phosphoryloxy enecarbamates. A highly chemoselective cross-coupling of N-(o-bromophenyl)-alpha-phosphoryloxyenecarbamates with boron nucleophiles enabled the efficient preparation of various N-(o-bromophenyl)enecarbamates, which served as useful precursors for subsequent Heck-type cyclization or 5-endo-trig aryl radical cyclization to furnish 2-substituted indoles or indolines, respectively.     

Cu催化吲哚啉的炔丙基烷基化/脱氢对映选择性合成手性N-炔丙基吲哚化合物(英文)

基于吲哚啉的Cu催化不对称炔丙基烷基化及DDQ脱氢策略,成功合成了手性N-炔丙基吲哚化合物.通过使用一个结构刚性的酮亚胺三齿P,N,N-配体,反应获得了很好的对映选择性.该方法反应条件温和、底物适用范围广、产物收率高、立体选择性好,为手性N-炔丙基吲哚化合物的合成提供了一条简捷、高效的新途径.     

Routes toward enantiopure 2-substituted indolines: an overview

Chiral-2-substituted indolines are an important class of compounds with numerous applications in organic synthesis and as constituents of a number of biologically active molecules. Consequently, there has been a continued interest in the development of efficient methods for the syntheses of this class of chiral compounds. In this review, a detailed survey of the important efforts toward the synthesis of enantioenriched 2-substituted indolines by means of the kinetic resolution or the use of a chiral auxiliary in stoichiometric or catalytic processes is provided. The resolution of racemic mixtures through diastereomeric separation is not considered in the article.     

Rhodium-catalyzed oxidative homologation of N-pyrimidyl indolines with alkynes via dual C—H activation: Facile synthesis of benzo[g] indolines

An efficient route to benzo[g]indolines by a rhodium-catalyzed C6- and C7 H functionalization of indolines with alkynes was achieved, which is potentially applicable to the synthesis of benzo[g] indoles through oxidation/removal of the directing group.     

Titanocene(III)-catalyzed formation of indolines and azaindolines

Reductive cyclization of epoxides tethered to substituted anilines and aminopyridines in the presence of 3 mol % of titanocene dichloride and stoichiometric manganese metal promotes a radical annulation to form 3,3-disubstituted indolines and azaindolines.     

One-pot cyclization of 2-aminophenethyl alcohols: a novel and direct approach to the synthesis of N-acyl indolines

A unique one-pot cyclization of 2-aminophenethyl alcohols with carboxylic acids in the presence of PPh3, CCl4, and NEt3 furnished the formation of N-acyl indolines in good to excellent yields. This new approach provides an efficient, scalable, low-cost, and direct access to the biologically important indolines which are further oxidizable to indoles and oxindoles.     

Enantioselective gold-catalyzed synthesis of polycyclic indolines

The synthesis of architecturally complex polycyclic fused indolines is achieved in a chemo-, regio-, and stereodefined manner, via an enantioselective gold-catalyzed cascade hydroindolination/iminium trapping synthetic sequence. Highly functionalized tetracyclic fused furoindolines (2) and dihydropyranylindolines (4) are synthesized in moderate to good yields and enantiomeric excesses of up to 87%.     

Synthesis of indolines, indoles, and benzopyrrolizidinones from simple aryl azides

A simple approach to prepare indolines and benzopyrrolizidinones from ortho-azidoallylbenzenes via a tandem radical addition/cyclization is described. The use of triethylborane to initiate and sustain the process provides the best results. Indolines are easily converted into the corresponding indoles by oxidation with manganese dioxide.     

Synthesis of highly substituted indolines and indoles via intramolecular [4 + 2] cycloaddition of ynamides and conjugated enynes

Ynamides react with conjugated enynes in intramolecular [4 + 2] cycloadditions to afford substituted indolines that undergo oxidation with o-chloranil to furnish the corresponding indoles. The cycloaddition substrates are easily assembled from derivatives of 3-butynylamine by Sonogashira coupling with alkenyl halides followed by copper-catalyzed N-alkynylation with acetylenic bromides. Diynamides participate as particularly reactive 2pi components in the cycloaddition, providing access to indolines with carbon substituents at the C-7 position. Enynamides serve as 4pi components in a complementary version of the cycloaddition strategy which provides access to indoles and indolines substituted with carbon substituents at C-4. These enyne cycloadditions take place upon heating the substrates at 110-210 degrees C in toluene or 2,2,2-trifluoroethanol and in some cases can be achieved at 0 degrees C to room temperature in the presence of Lewis acids such as Me2AlCl.     

Efficient construction of fused indolines with a 2-quaternary center via an intramolecular Heck reaction with a low catalyst loading

An efficient construction of fused indolines with a 2-quaternary center through a palladium-catalyzed intramolecular Heck reaction of N-(2(2-halobenzoxyl)-2,3-disubstituted indoles is disclosed. This protocol provided a straightforward access to diverse fused indolines with good functional group tolerance.     

Synthesis of indolines and tetrahydroquinolines fromortho-(alk-2-enyl)anilines

Intramolecular cyclization ofo-alkenylanilines was studied. Heating ofo-(cyclopent-2-en-1-yl) arylammonium chlorides at 200–220 °C yields cyclopenta[b]indolines as the main reaction products. Cyclization of 4-methyl-2-(pent-3-en-2-yl)aniline under the same conditions gave a mixture of indolines and tetrahydroquinolines. An alk-1-enylarylamine containing a vinylic double bond does not form cyclization products on the nitrogen atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 975–978, May, 1999.     

Reductive nitro-mannich route for the synthesis of 1,2-diamine containing indolines and tetrahydroquinolines

A one-pot, 1,4-hydride addition nitro-Mannich reaction between a set of nitroalkenes 3 and a wide range of N-p-methoxyphenyl-protected aldimines, derived from alkyl, aryl and heteroaryl aldehydes, followed by Zn/HCl reduction leads to stereochemically defined 1,2-diamines. These underwent palladium-catalyzed cyclization and depending upon the presence or not of the trifluoroacetamide protecting group gave either tetrahydroquinolines 18 or indolines 14 in high overall yield and diastereoselectivity (19 examples each). In each case, the more nucleophilic pendant amine cyclizes to give a benzofused saturated heterocyclic 5- or 6-membered ring, with an additional vicinal amino stereocenter in each.     

One-pot synthesis of substituted indolines via a copper-catalyzed sequential multicomponent/C-N coupling reaction

One-pot synthesis of 2-(N-sulfonylimino)indolines has been developed. The procedure combines the copper-catalyzed three-component reaction of sulfonyl azides, o-bromophenylacetylenes, and amines and the copper-catalyzed intramolecular C-N coupling in one sequence, which afforded the products in moderate to good yields. The resulting 2-(N-sulfonylimino)indolines could be easily transformed to pharmaceutically valuable oxindoles (indolin-2-ones).