Aniline Dearomatization and Silver-Catalyzed [3+3] Dipolar Cycloaddition: Efficient Construction of Oxocino[4,3,2-cd]indoles from 2-Alkynylanilines and 2-Alkynylbenzaldoximes

A Diastereoselective Cascade Annulation Approach to Bridged Polycyclic Heterocycles Involving an Unexpected Rearrangement

A diastereoselective cascade annulation between allenoates and in-situ generated isoquinoline N-oxides generating sp³-rich bridged polycyclic heterocycles is disclosed. The reaction proceeds through an unprecedented non-rearomatized rearrangement and allows access to a broad range of bridged heterocycles in 38-93% yields with excellent functional group tolerance and high diastereoselectivity. Density functional theory calculations provided key insights into the possible reaction pathway and the stereoselectivity of this procedure.

Dearomatization [4+2] Cycloaddition of Nonactivated Benzene Derivatives

Dearomatization reactions have recently emerged as a powerful tool for the rapid buildup of molecular complexity. Here, an unparalleled thermal dearomatization [4+2] cycloaddition reaction between benzene derivatives and a 2H-phosphindole tungsten complex was reported. The unique reactivity of the in situ-generated 2H-phosphindole complex toward benzene was revealed by density functional theory calculations. We thus provide new insights into the dearomatization of nonactivated arenes and pave the way for the manipulation of the dearomatization for further applications.

Anodic dearomatization of 2-alkynylanilines for the synthesis of multi-functionalized indoles

An anodic oxidative dearomatization reaction of 2-alkynylanilines was developed. The formed dearomatized compounds were used as versatile precursors in the synthesis of a variety of benzenoid ring multi-functionalized indoles through simple conversions.

Synthesis of functionalized 1-aminoisoquinolines through cascade three-component reaction of ortho-alkynylbenzaldoximes, 2H-azirines, and electrophiles

We have developed a new three-component approach using ortho-alkynylbenzaldoximes involving the formation of a cyclic nitrone in the presence of Br₂ or ICl for the synthesis of 1-aminoisoquinolines via cascade 6-endo-cyclization, 1,3-dipolar cycloaddition reaction with 2H-azirines, and ring-opening reaction sequences. The broad range of structurally diverse products, good to high yields, high atom-economy and high bond-formation efficiency make this method an attractive alternative for the synthesis of 1-aminoisoquinolines.

Divergent synthesis of 4-amino indoles with free amine groups via tandem reaction of 2-alkynylanilines

A dearomatization method for divergent synthesis of 4-amino indoles having N1 or C4 free amine groups from 2-alkynylanilines was reported.

Synthesis of 4-Alkylindoles from 2-Alkynylanilines via Dearomatization- and Aromatization-Triggered Alkyl Migration

A simple method for rapid synthesis of 4-alkylindoles from 2-alkynylanilines was reported. The protocol involves an oxidative dearomatization and an aromatization triggered regioselective alkyl migration. A range of alkyl groups including linear, branched, or cycloalkyl groups can be introduced into the C4 position of indole.

Facile synthesis of 4-acetoxyindoles via PhI(OAc)2-mediated dearomatization of 2-alkynylanilines

A simple process for rapid synthesis of 4-aetoxyindoles from readily available 2-alkynylanilines via dearomatization was reported.

Synthesis of N-indolated amino acids or peptides from 2-alkynylanilines via a dearomatization process

A process for the rapid synthesis of N-indolated amino acids or peptides from readily available 2-alkynylanilines via dearomatization was reported.

Synthesis of 4,7-Difunctionalized Indoles via Imino Exchange and Sulfinyl Migration

A process that rapidly assembles 4,7-difunctionalized indoles from 2-alkynycyclohexadienimines, sulfinamides, and nucleophiles (amines or alcohols) was developed. The process involves imino exchange, cascade cyclization/1,4-nucleophilic addition/aromatization, and 1,3-migration of the sulfinyl group. The 7-sulfinyl group is easy to convert into the sulfonyl or the thioether group through a simple oxidation and reduction reaction.

Catalytic asymmetric chemodivergent arylative dearomatization of tryptophols

The first catalytic asymmetric arylative dearomatization of tryptophols has been established. By using quinone imine ketals as aryl group surrogates and modulating the reaction conditions, the cascade reaction of tryptophols with quinone imine ketals afforded two series of arylative dearomatization products in generally high yields, and excellent diastereo- and enantioselectivities.

PhI(OAc)2-mediated dialkoxylation of 4-aminostyrenes through a dearomatization process under metal-free conditions

A PhI(OAc)₂-mediated dialkoxylation of 4-aminostyrenes has been developed to afford 2,3-disubstituted 1,4-dioxane or 1,2-dimethoxyethane derivatives.