Ruthenium-Catalyzed Cycloisomerization of 2-Alkynylanilides: Synthesis of 3-Substituted Indoles by 1,2-Carbon Migration
作者:Takuma Watanabe、Yuichiro Mutoh、Shinichi Saito
DOI:10.1021/jacs.7b04564
日期:2017.6.14
We developed ruthenium-catalyzedcycloisomerization of alkynylanilides that gave 3-substituted indoles in high yields. The reaction proceeded via the disubstituted vinylidene ruthenium complex that was formed by the 1,2-carbon migration.
A copper-catalyzed annulative amination approach to 3-aminobenzofurans and -indoles from o-alkynylphenols and -anilines has been developed. The Cu-based catalysis is based on an umpolung, electrophilic amination with O-benzoyl hydroxylamines and enables the mild and convergent synthesis of various 3-aminobenzoheteroles of biological and pharmaceutical interest. Some mechanistic investigations and an application of this protocol to construction of more complex tricyclic framework are also described.
Dehydrogenative Synthesis of C3-Azolylindoles via Copper-Promoted Annulative Direct Coupling of o-Alkynylanilines
A copper-promoted annulative direct coupling of o-alkynylaniline derivatives with 1,3,4-oxadiazoles for the synthesis of C3-azolylindoles has been developed. The copper-based system provides a new protocol for the dehydrogenative construction of indole-oxadiazole conjugations from nonhalogenated and non-metalated starting materials.
Synthesis of 3,1-Benzothiazines from 2-Alkenyl- and 2-Alkynylanilides and Lawesson Reagent
Reaction of 2-vinylacetanilide with P4S10 gave 2-vinylthioacetanilide, whereas reaction of 2-vinylacetanilide with Lawesson reagent (LR) afforded 2,4-dimethyl-4H-3,1-benzothiazine in 62% yield. Reaction of 2-alkynylanilides with LR gave 4-exomethylene-4H-3,1-benzothiazines in good yields.