Nickel-Catalyzed Enantioselective Dearomative Heck-Reductive Allylic Defluorination Reaction of Indoles

Herein, we describe a nickel-catalyzed asymmetric dearomative aryl-difluoroallylation reaction of indoles with α-trifluoromethyl alkenes as an electrophilic coupling partner. The reaction proceeds via a cascade sequence involving dearomative Heck cyclization and reductive allylic defluorination. A series of gem-difluoroallyl substituted indolines are obtained in moderate to good yields (36-77% yield) with excellent enantioselectivity (up to 99% ee). The reaction features broad functional group tolerance, scaled-up synthesis, and late-stage diversification.

Access to Benzocyclic Boronates via Light-Promoted Intramolecular Arylborylation of Alkenes

Benzocyclic boronates have attracted increasing research interest in drug chemistry and organic synthesis in recent years. Herein, we report a facile access to benzocyclic boronates through photopromoted intramolecular arylborylation of allyl aryldiazonium salts. This simple protocol features a broad scope, allowing the formation of variously functionalized borates bearing dihydrobenzofuran, dihydroindene, benzothiophene, and indoline skeletons under mild and sustainable conditions.

Dearomatizing [2+2+1] Spiroannulation of Indoles with Alkynes

A palladium-catalyzed dearomatizing [2+2+1] spiroannulation of indoles with two molecular internal alkynes is developed in the presence of Cu(OAc)₂/O₂ as the oxidant, in which a domino sequence including C-H activation of indole followed by consecutive Heck reactions is involved. A range of 3,3'-spiroindolines bearing tetrasubstituted cyclopentadiene moieties and exocyclic C═C bonds at C2 are obtained in moderate to excellent yields.

Enantioselective difunctionalization of alkenes by a palladium-catalyzed Heck/borylation sequence

A palladium catalyzed enantioselective Heck/borylation reaction of alkene-tethered aryl iodides was realized, delivering a variety of 2,3-dihydrobenzofuranyl boronic esters in high yield with excellent enantioselectivity. Asymmetric synthesis of chromane boronic ester, indane boronic ester and indoline boronic ester was also accomplished. The protocol offers an efficient access to the corresponding chiral benzocyclic boronic esters, which are notably important chemical motifs in synthetic transformations.

A palladium catalyzed enantioselective Heck/borylation reaction of alkene-tethered aryl iodides was realized, delivering a variety of 2,3-dihydrobenzofuranyl boronic esters in high yield with excellent enantioselectivity.

Synthesis of functionalized 3,2′-pyrrolidinyl spirooxindoles via domino 1,6-addition/annulation reactions of para-quinone methides and 3-chlorooxindoles

A highly efficient diastereoselective [4 + 1] cycloaddition of ortho-tosylaminophenyl-substituted p-QMs with 3-chlorooxindoles has been developed to afford 3,2′-pyrrolidinyl spirooxindoles.

Nickel-Catalyzed Dearomative Arylboration of Indoles: Regioselective Synthesis of C2- and C3-Borylated Indolines

Indole dearomatization is an important strategy to access indolines: a motif present in a variety of natural products and biologically active molecules. Herein, a method for transition-metal catalyzed regioselective dearomative arylboration of indoles to generate diverse indolines is presented. The method accomplishes intermolecular dearomatization of simple indoles through a migratory insertion pathway on substrates that lack activating or directing groups on the C2- or C3-positions. Synthetically useful C2- and C3-borylated indolines can be accessed through a simple change in N-protecting group in high regio- and diastereoselectivities (up to >40:1 rr and >40:1 dr) from readily available starting materials. Additionally, the origin of regioselectivity was explored experimentally and computationally to uncover the remarkable interplay between carbonyl orientation of the N-protecting group on indole, electronics of the C2-C3 π-bond, and sterics. The method enabled the first enantioselective synthesis of (-)-azamedicarpin.

Enantioselective assembly of 3,3-disubstituted succinimides via three-component reaction of vinyl diazosuccinimides with alcohols and imines

An enantioselective three-component reaction of vinyl diazosuccinimdes with alcohols and imines has been realized by a cooperative catalysis of Rh2(OAc)4 and a chiral phosphoric acid, leading to chiral 3,3-disubstituted succinimides in good to high yields with high to excellent enantioselectivity. The generated product with an alkenyl species could be converted to the chiral tricyclic structure under mild conditions.

A Pd-catalyzed domino Larock annulation/dearomative Heck reaction

A highly efficient synthesis of indolines from N-bromobenzoyl o-iodoanilines and alkynes is developed via a domino Larock annulation/dearomative Heck reaction.

Synthesis of tetracyclic indolin-3-ones through Pd-catalyzed intramolecular deacetylative dearomatization of 3-acetoxy-indoles

An efficient palladium-catalyzed intramolecular deacetylative dearomatization reaction of 3-acetoxyindoles has been developed. A range of tetracyclic indolin-3-ones bearing C2-quaternary stereocenters are achieved in good yields, showing a wide substrate scope for this reaction. A preliminary enantioselective reaction is established to furnish the product in 63% ee by using (R,R,R)-phosphoramide-PE as a chiral ligand.

An efficient palladium-catalyzed intramolecular deacetylative dearomatization reaction of 3-acetoxyindoles is disclosed, affording tetracyclic indolin-3-ones bearing C2-quaternary stereocenters in good yields.

Pd-catalyzed dearomative arylborylation of indoles

A palladium-catalyzed dearomative arylborylation of indoles is reported, which provides straightforward access to structurally diverse indolines bearing vicinal tetrasubstituted and borylated trisubstituted stereocenters in moderate to good yields with excellent diastereoselectivities.

Palladium-catalyzed dearomative arylphosphorylation of indoles

A palladium-catalyzed dearomative arylphosphorylation reaction of indoles involving C–C/C–P bond formation is developed.

Cu/Pd cooperatively catalyzed tandem intramolecular anti-Markovnikov hydroarylation of unsaturated amides: facile construction of 3,4-dihydroquinolinones via borylation/intramolecular C(sp3)–C(sp2) cross coupling

An anti-Markovnikov hydroarylation of unsaturated amides via a Cu/Pd synergistically catalyzed cascade borylation/intramolecular sp²–sp³ cross coupling has been disclosed.

Palladium-catalyzed asymmetric dearomative alkenylation of indoles through a reductive-Heck reaction

A highly enantioselective intramolecular dearomatizing olefination of indoles has been developed through a Pd-catalyzed reductive Heck reaction.

Spirooxindole synthesis via palladium-catalyzed dearomative reductive-Heck reaction

Synthesis of 3,2′-spiropyrrolidine oxindole scaffolds via palladium-catalyzed intramolecular dearomative reductive-Heck reaction and [2,3-b]quinolinones through direct C3-arylation.