Yun Liang

By tuning the bromine substituent position in chalcones, we herein developed a palladium-catalyzed divergent C–H activation/decarboxylative cyclization with o-halobenzoic acids. Substrates bearing the bromine at the ortho position of the styrenyl moiety, namely (E)-1-(2-bromophenyl)-3-phenylprop-2-en-1-ones, undergo a Heck cyclization, oxidative dehydrogenation, C–H activation, and decarboxylation cascade to afford phenanthrene-fused indanones. In addition, the isomeric (E)-3-(2-bromophenyl)-1-phenylprop-2-en-1-ones selectively deliver 9-acylphenanthrenes. This protocol features excellent regioselectivity and broad substrate compatibility.

We report a palladium-catalyzed vinyl C–H silylation of vinyl bromides/triflates involving C (vinyl), C (alkyl)-palladacycles for the synthesis of 1,4-disilylated 1,3-butadienes.

A photochemical strategy enabling tandem cyclization and dearomatization of ortho-sulfonamide-tethered alkylidenecyclopropanes via N-centered radicals has been developed under metal-free conditions. The reaction employs an organic fluorophore 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as a photocatalyst. This mild and operationally simple photocatalytic system demonstrates that the sulfonamidyl-radical-mediated intramolecular olefin amination effectively integrates radical ring opening with dearomatization pathways, thereby facilitating the synthesis of diverse fused seven-membered cyclic sulfonamides with a broad substrate scope, high regioselectivity, and excellent product diversity.

Herein, we report a palladium/norbornene-catalyzed trifunctionalization of ortho-unsubstituted aryl iodides involving three C-H activations. This transformation employs anhydrides and benzyl bromides as different electrophiles to achieve ortho-C-H benzylation and acylation followed by intramolecular ipso-arylation, thus constructing 4-acyl-9H-fluorenes. Furthermore, the reaction can synthesize 4-acyl-9H-fluorenones via double ortho-C-H acylation and subsequent cyclization under benzyl bromide-free conditions. This protocol demonstrates excellent chemo- and regioselectivity, along with broad substrate scope.

Herein, we report a 1,4-Pd migration-enabled intermolecular double C-H annulation between alkene-tethered aryl halides (e.g., 2-iodo-N-methacryloylbenzamides and 2-(2-iodophenyl)-1H-indoles) and 1,n-diynes. This transformation proceeds through a cascade sequence involving Heck cyclization, alkyl-to-aryl 1,4-Pd migration, double alkyne insertion, and C-H activation, enabling the remote construction of structurally diverse heteropolycycles, including tetracyclic fused isoquinolinediones and hexacyclic indolo[2,1-a]isoquinolinones. The method exhibits a broad substrate scope and excellent regioselectivity.

We herein report a palladium-catalyzed dearomative Heck/C(sp²)-H activation/[4 + 2] decarboxylative cyclization of C2-tethered indoles. In this transformation, the alkylpalladium(II) species generated by indole dearomatization undergoes C-H activation to form C,C-palladacycles, which are subsequently trapped by o-bromobenzoic acids or cyclic β-bromoacrylic acids, enabling regio- and diastereoselective construction of hexacyclic and octocyclic fused indolines with a broad substrate scope.

Herein, a palladium-catalyzed regiodivergent oxypalladation/C-H annulation for the synthesis of polyarene-fused isocoumarins using different alkynylaryl carboxylate substrates as a controlled switch is reported. When o-alkynylbenzoates are employed to react with o-bromobenzoic acids, tribenzo[c,f,h]chromen-6-ones are synthesized by sequential 6-endo cyclization, C-H activation, and decarboxylative cyclization. Using 8-(alkynyl)-1-naphthoates as the substrates enables the construction of benzo[g]naphthochromen-4-ones via a 6-exo cyclization/C-H activation process.

A readily accessible dimethoxytetramethyldisilane has been developed for overcoming the limitations of palladium-catalyzed C–H silacyclization of 2-iodobiphenyls, thus enabling divergent synthesis of dibenzooxadisilepines and dibenzosiloles.

An alkyne insertion/vinyl to aryl 1,5-palladium migration strategy has been disclosed for the α-C–H silylation and boronation of a naphthalene ring, enabling the synthesis of silylated and boronated benzo[ f ]isoquinolines and benzo[ f ]isochromenes.

A palladium-catalyzed dearomative Heck/[4 + 3] decarboxylative cyclization of indoles with α-oxocarboxylic acids via C−H activation is reported, which offers an efficient avenue for assembling fused indolines containing a seven-membered ring.