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A cyclopropanation/intramolecular rearrangement initiated by the Michael addition of in situ generated ortho‐quinone methides (o‐QMs) has been developed for the enantioselective synthesis of 2‐aryl‐2,3‐dihydrobenzofurans containing two consecutive stereogenic centers, including a quaternary carbon atom. In the presence of a chiral oxazaborolidinium ion catalyst, the reaction proceeded in excellent yields (up to 95 %) with excellent stereoselectivity (up to >99 ee, up to >20:1 d.r.). [ABSTRACT FROM AUTHOR]

A novel and facile iron-catalyzed tandem annulation of o-phenylenediamines and diazocarbonyls in water for the construction of polyfunctionalized quinoxalines has been developed. The key strategy includes the one-pot domino N−H insertion, cyclization, and oxidation reactions. This protocol offers a safe and mild synthetic approach to access a variety of quinoxaline derivatives in high yields. This methodology also allows the formation of biologically interesting pyrazines and benzoquinoxalines. [ABSTRACT FROM AUTHOR]

Biologically interesting 2-aryl-2,3-dihydroquinolin-4(1H)- ones were synthesized using a mild and efficient one-pot procedure starting from o-aminoacetophenones and aromatic aldehydes in the presence of silver(I) triflate. This synthetic protocol provides rapid access to a variety of 2-aryl-2,3-dihydroquinolin-4(1H)-ones. This technique has several advantages, such as the use of easily available starting materials, the efficiency of the catalyst, a simple operation, and tolerance of a wide range of functionality in the aldehydes. Screening of the synthesized compounds for their antioxidant properties revealed that two compounds (with EC50 = 15.42 μM and 15.16 µM) exhibit a potent free-radical scavenging ability towards TEAC free radicals compared to the standard, Trolox. [ABSTRACT FROM AUTHOR]

A variety of multisubstituted azopyrazoles were synthesized in good yield from an efficient one-pot silver trifluoromethanesulfonate (AgOTf)-catalyzed cascade reaction of α-diazo-β-keto esters with two arylhydrazines or two arylhydrazine hydrochlorides. This cascade reaction included pyrazolone formation, NH insertion, and oxidation. For the synthesis of more diverse azopyrazoles bearing two different aromatic rings, the silver(I)-catalyzed cascade reaction of 4-diazopyrazol-3-one with arylhydrazine hydrochlorides was also developed. The advantages of these methodologies are easy handling, mild reaction conditions, and an effective and non-toxic catalyst usage. [ABSTRACT FROM AUTHOR]

The direct arylation of C( sp3)H bonds adjacent to oxygen in ethers with phenol and naphthol derivatives was developed via palladium(II) acetate/copper(II) triflate [Pd(OAc)2/Cu(OTf)2]-catalyzed cross-dehydrgenative coupling in the presence of tert-butyl hyroperoxide (TBHP). This process provides exclusive installation of a tetrahydrofuranyl moiety at a more hindered position of multiply substituted phenol derivatives. The cross-dehydrogenative coupling of 1,4-dihydroxynaphthalene with cyclic ethers and free alcohols afforded biologically interesting 2-substituted 1,4-naphthoquinone derivatives. [ABSTRACT FROM AUTHOR]

A new synthetic route for biologically interesting pyranocarbazoles was developed by reaction of 2- or 4-hydroxycarbazole with α,β-unsaturated aldehydes in the presence of ethylenediamine diacetate (EDDA). The key strategy of this methodology is a formal [3+3] cycloaddition via domino aldol-type/6π- electrocyclization. The synthesized pyranocarbazoles can be converted into derivatives bearing substituents on the carbazole and pyran rings. [ABSTRACT FROM AUTHOR]

A three-component cyclization reaction of β-keto esters with two equivalents of arylhydrazines yields (arylazo)pyrazoles via an in situ α-iodination of the β-keto esters, pyrazol-3-one formation, nucleophilic substitution, and aromatization cascade. [ABSTRACT FROM AUTHOR]

The title quinolinones are efficiently obtained under mild reaction conditions starting from a variety of o-aminoacetophenones and aryl aldehydes. [ABSTRACT FROM AUTHOR]

The title azopyrazoles are obtained by reaction of various α-diazo-β-keto esters with arylhydrazines or arylhydrazine hydrochlorides involving a cascade pyrazolone formation, N-H insertion, and oxidation. [ABSTRACT FROM AUTHOR]

The front cover picture, provided by Yong Rok Lee and co ‐ worker, illustrates the catalytic application of silver for the construction of multifunctionalized azopyrazoles via cascade reaction of a ‐ diazo ‐ b ‐ keto esters and arylhydrazines. The synthesis of azopyrazoles bearing two different aromatic rings from 4 ‐ diazopyrazol ‐ 3 ‐ ones and aryhydrazine hydrochlorides is a unique advantage of this protocol. Silver ‐ catalyzed in situ pyrazole formation, N–H insertion, and oxidation have great potential for the advancement in the area of carbenoid chemistry. Details can be found in the full paper on pages 2657 – 2664 (R. P. Pandit, Y. R. Lee, Adv. Synth. Catal.­ 2015, 357, 2657 – 2664; DOI: 10.1002/adsc.201500197 [ABSTRACT FROM AUTHOR]

A facile protocol is developed for the cross-dehydrogenative coupling of ethers and alcohols with phenol and naphthol derivatives. [ABSTRACT FROM AUTHOR]

Wolff rearrangement of α-diazo-β-ketoesters (I) and (IV) followed by trapping of the ketene intermediates with enol ethers (II) and (V) generates a variety of trans-γ,δ-unsaturated β-ketoesters (III) and (VI), respectively. [ABSTRACT FROM AUTHOR]

Biologically interesting title heterocycles are prepared under conditions A). [ABSTRACT FROM AUTHOR]