Palladium-catalyzed picolinamide-directed iodination of remote ortho-C−H bonds of arenes: Synthesis of tetrahydroquinolines
نویسندگان
چکیده
A new palladium-catalyzed picolinamide (PA)-directed ortho-iodination reaction of ε-C(sp(2))-H bonds of γ-arylpropylamine substrates is reported. This reaction proceeds selectively with a variety of γ-arylpropylamines bearing strongly electron-donating or withdrawing substituents, complementing our previously reported PA-directed electrophilic aromatic substitution approach to this transformation. As demonstrated herein, a three step sequence of Pd-catalyzed γ-C(sp(3))-H arylation, Pd-catalyzed ε-C(sp(2))-H iodination, and Cu-catalyzed C-N cyclization enables a streamlined synthesis of tetrahydroquinolines bearing diverse substitution patterns.
منابع مشابه
Synthesis of phenanthridines via palladium-catalyzed picolinamide-directed sequential C–H functionalization
We report a new synthesis of phenanthridines based on palladium-catalyzed picolinamide-directed sequential C-H functionalization reactions starting from readily available benzylamine and aryl iodide precursors. Under the catalysis of Pd(OAc)2, the ortho-C-H bond of benzylpicolinamides is first arylated with an aryl iodide. The resulting biaryl compound is then subjected to palladium-catalyzed p...
متن کاملCombined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans
A new route to regioselectively dialkoxy-functionalized benzo[b]furan derivatives has been developed from 3-halo-2-iodoanisoles bearing an additional methoxy group, which have been accessed through an ortho-zincation/iodination reaction. Two palladium-catalyzed processes, namely a Sonogashira coupling followed by a tandem hydroxylation/cyclization sequence, give rise to new and interesting dime...
متن کاملCopper-catalyzed ortho-halogenation of arenes and heteroarenes directed by a removable auxiliary.
Copper-catalyzed ortho-halogenation of C(sp(2))-H bonds directed by a PIP directing group with NXS (X = Cl, Br, I) has been developed. The reaction is scalable and tolerates a broad range of functional groups and heteroarenes, providing an efficient access to halogenated arenes and heteroarenes.
متن کاملPalladium-catalyzed direct functionalization of 2-aminobutanoic acid derivatives: application of a convenient and versatile auxiliary.
The last decade has witnessed great progress on transitionmetal-catalyzed C H bond functionalization. Although many synthetically useful methods for regioselective functionalization of the C(sp) H bond of arenes and heteroarenes have been discovered, direct functionalization of C(sp) H bonds in common alkyl groups is still challenging. This challenge arises from the inert nature of most C(sp) H...
متن کاملPalladium-catalyzed ortho-halogenations of acetanilides with N-halosuccinimides via direct sp2 C–H bond activation in ball mills
A solvent-free palladium-catalyzed ortho-iodination of acetanilides using N-iodosuccinimide as the iodine source has been developed under ball-milling conditions. This present method avoids the use of hazardous organic solvents, high reaction temperature, and long reaction time and provides a highly efficient methodology to realize the regioselective functionalization of acetanilides in yields ...
متن کامل