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Presented herein is the synthesis of diversely functionalized pyrrolizines from the reaction of N-alkoxycarbamoyl pyrroles with CF3-ynones. The formation of the product is based on a C–H bond activation-initiated cascade process including N-alkoxycarbamoyl group-directed alkenylation of the pyrrole scaffold followed by simultaneous intramolecular nucleophilic addition along with cleavage and transfer of the directing group. By taking advantage of the rich chemistry of the transferred alkoxycarbamoyl moiety, the products could be transformed into a series of structurally and biologically interesting pyrrolizine derivatives. To our knowledge, this is the first example in which the N-alkoxycarbamoyl unit acted as a transferable and transformable directing group for the divergent synthesis of pyrrolizines. [ABSTRACT FROM AUTHOR]

A novel synthesis of diversely substituted 2,2′-biphenols through Pd(ii)-catalyzed, tBuOOH-oxidized, and hydroxyl-directed C(sp2)–H hydroxylation of [1,1′-biphenyl]-2-ols has been developed. Notably, this finding is distinct from previous reports in which [1,1′-biphenyl]-2-ols underwent an intramolecular C–H activation and C–O bond formation to afford dibenzofurans under the promotion of Pd(ii) but in the absence of tBuOOH. [ABSTRACT FROM AUTHOR]

Presented herein are novel syntheses of CF 3 -isoquinolinones and imidazole fused CF 3 -isoquinolinones based on the cascade reactions of 2-aryloxazolines with trifluoromethyl imidoyl sulfoxonium ylides. The formation of CF 3 -isoquinolinone involves an intriguing cascade process including oxazolinyl group-assisted aryl alkylation through C(sp 2 )-H bond metalation, carbene formation, migratory insertion, and proto-demetalation followed by intramolecular condensation and water-promoted oxazolinyl ring-scission. With this method, the isoquinolinone scaffold tethered with valuable functional groups was effectively constructed. By taking advantage of the functional groups embedded therein, the products thus obtained could be readily transformed into imidazole-fused CF 3 -isoquinolinones or coupled with some clinical drugs to furnish hybrid compounds with potential applications in drug development. In general, the developed protocols feature expeditious and convenient formation of valuable CF 3 -heterocyclic skeletons, broad substrate scope, and ready scalability. In addition, studies on the activity of selected products against some human cancer cell lines demonstrated their potential as lead compounds for the development of novel anticancer drugs.

Presented herein is an unprecedented synthesis of naphtho[1',2':4,5]furo[3,2- b ]pyridinones via Ir(III)-catalyzed C6/C5 dual C-H functionalization of N -pyridyl-2-pyridones with diazonaphthalen-2(1 H )-ones. This protocol forms C-C and C-O bonds in one pot in which diazonaphthalen-2(1 H )-ones serve as bifunctional reagents, providing both alkyl and aryloxy sources. To the best of our knowledge, this is the first example of an Ir(III)-catalyzed synthesis of the title compounds by using diazonaphthalen-2(1 H )-ones as bifunctional substrates. Notably, this method features operational simplicity, good functional group tolerance, high efficiency, and high atom economy.

In this paper, an efficient synthesis of N -arylindoles through the cascade reaction of 2-alkenylanilines with diazonaphthalen-2(1 H )-ones is presented. Mechanistically, this reaction involves the generation of a Ru-carbene complex from diazonaphthalen-2(1 H )-one, followed by carbene N-H bond insertion with 2-alkenylaniline, intramolecular cyclization, and oxidative aromatization. In this reaction, the Ru(II) complex acts as a multifunctional catalyst to promote not only the carbene formation but also the intramolecular cyclization and the dehydrogenative aromatization. Meanwhile, air acts as a green and cost-effective oxidant. To our knowledge, this is the first example in which N -arylindoles were synthesized through simultaneous introduction of the N -aryl unit and construction of the indole scaffold. Notable advantages of this method include readily accessible and halide-free substrates, additive-free reaction conditions, good efficiency, excellent atom economy, and compatibility with diverse functional groups. In addition, the utility of the product thus obtained was showcased by its diverse structural transformations.

Presented herein is an efficient and unprecedented synthesis of indolyl-tethered spiro[cyclobutane-1,1'-indenes] through the cascade reaction of 1-(pyridin-2-yl)-1 H -indoles with alkynyl cyclobutanols. Mechanistic experiments implicate a sequential process in which 1-(pyridin-2-yl)-1 H -indole first undergoes an alkenylation with alkynyl cyclobutanol followed by an intramolecular Friedel-Crafts reaction to give the title products. The utility of this novel protocol was reflected by the ample substrate scope, high chemo- and regioselectivity, removable directing group, and scalable preparation. In addition, the product thus obtained can be further derivatized quite efficiently.

An unprecedented divergent synthesis of pyrazolo[1,2- a ]pyrazolones and 2-acylindoles via Rh(III)-catalyzed [4 + 1] or [3 + 2] annulation of 1-phenylpyrazolidinones with alkynyl cyclobutanols through redox-neutral multiple bond activation by using -NH and -OH units as directing groups is presented. Notably, different annulation reactions were selectively achieved by simply adjusting the reaction conditions. With features such as simple procedures, easily accessible substrates, and high regio/chemoselectivity, these methods may find wide applications in related areas.

In this paper, a novel and sustainable synthesis of the hitherto unreported 5H-benzo[c]imidazo[1,2-a]azepine-6-carboxylic acids via the cascade reactions of 2-arylimidazoles (1) with methylene-oxetanones (2) is presented. Mechanistically, the formation of the title compounds is triggered by a Rh(iii)-catalyzed C(sp 2 )-H alkenylation of 1 with 2 followed by an intramolecular N-nucleophilic substitution. With this method, a series of hybrid compounds combining the biologically promising imidazole and benzoazepine moieties decorated with a synthetically versatile carboxyl group were prepared in moderate to good efficiency. In addition, the utility of the products thus obtained was remarkably showcased by their efficient transformations into some otherwise difficult-to-obtain pentacyclic compounds.