Recent Developments in Radical Cross‐Coupling of Redox‐Active Cycloketone Oximes

Abstract Recent years have witnessed a renaissance of radical cross‐coupling of cycloketone oximes which served as active cyanoalkyl radical via ring fragmentation in various transformations. It provided an efficient and practical strategy to introduce cyanoalkyl groups into organic compounds without using toxic cyanide sources. In this review, a comprehensive...

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Utilizing Alcohols for Cross‐Coupling with Alkenyl Bromides

The inside cover picture, designed by Takuya Suga, illustrates the merger of titanium‐mediated homolytic C–OH bond cleavage and nickel catalysis that realizes a cross‐coupling reaction between benzyl alcohols and alkenyl bromides. The direct application of alcohols to cross‐coupling may set us free from tedious preparations of halides and homolysis‐active...

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Reduction of Electron‐Deficient Alkenes Enabled by a Photoinduced Hydrogen Atom Transfer

Abstract Direct hydrogen atom transfer from a photoredox‐generated Hantzsch ester radical cation to electron‐deficient alkenes has enabled the development of an efficient formal hydrogenation under mild, operationally simple conditions. The HAT‐driven mechanism is supported by experimental and computational studies. The reaction is applied to a variety...

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Gold Catalysis Meets Materials Science – A New Approach to π‐Extended Indolocarbazoles

Abstract Herein we describe a modular, convergent synthesis of substituted benzo[a]benzo[6,7]‐indolo[2,3‐h]carbazoles (BBICZs) using a bidirectional gold‐catalyzed cyclization reaction as a key step. A building block strategy enabled the easy variation of substituents at different positions of the core structure and a general analysis of substitution...

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Recent Advances in the Synthesis of Heterocyclics via Cascade Cyclization of Propargylic Alcohols

Abstract Heterocyclic compounds are important organic compounds and have emerged as key scaffolds in numerous drugs, natural products, vitamins, biologically and pharmaceutically active compounds. Over the past few decades, the development of versatile methodologies employing propargylic alcohols as synthons for the construction of heterocyclic skeletons...

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Ruthenium Catalyzed C−H Amidation and Carbocyclization using Isocyanates: An Access to Amidated 2‐phenylphthalazine‐1,4‐diones and Indazolo[1,2‐b]phthalazine‐triones

Abstract A direct carbocyclization of 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones is achieved using isocyanates as carbonyl source via Ru(II)‐catalyzed sequential ortho‐amidation followed by intramolecular nucleophilic substitution, delivering substituted indazolo[1,2‐b]phthalazine‐triones in good‐to‐excellent yields. For ortho‐substituted 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones,...

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Copper‐Catalyzed Regio‐ and Stereoselective Oxidative Vinylsulfonylation of Quinoxalinones with Alkynes and Sulfonyl Hydrazides

Abstract An efficient approach to regio‐ and stereoselective synthesis of (Z)‐vinylsulfonylated quinoxalin‐2‐ones has been developed. This oxidative reaction involves copper‐catalyzed vinylsulfonylation of quinoxalin‐2(1H)‐ones with alkynes and sulfonyl hydrazides. Various functionalized vinylsulfonylated quinoxalin‐2(1H)‐one derivatives have been...

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Development of an Enzymatic Process for the Synthesis of the Key Intermediate of Telotristat Ethyl

Abstract (R)‐1‐(4‐chloro‐2‐(3‐methyl‐1H‐pyrazol‐1‐yl)phenyl)‐2,2,2‐trifluoroethan‐1‐ol [(R)‐2] is a key chiral intermediate in the synthesis of telotristat ethyl, an anti‐carcinoid syndrome drug. However, the synthetic methods for (R)‐2 mainly include chemical reductions, rarely involving biocatalysis or bioreduction until now. Here, we report a method...

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Gold‐Catalyzed Bicyclic and [3+2]‐Annulations of Internal Propargyl Alcohols with Nitrones and Imines To Yield to Two Distinct Heterocycles

Abstract A gold‐catalyzed synthesis of 1,3‐dihydrooxazolo[3,4‐a]indoles from 1‐oxo‐3‐yn‐4‐ols and nitrones is described; this new bicyclic annulation presents the first examples that internal alkynes can react with nitrones to undergo an oxoarylation route. DFT calculations indicate a [3,3]‐sigmatropic shift of initial alkenylgold intermediates to...

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Lewis Acid Catalyzed Reductive Cyclization of 2‐Aryloxybenzaldehydes and 2‐(Arylthio)benzaldehydes to Unsubstituted 9H‐Xanthenes and Thioxanthenes in Diisopropyl Ether

Abstract Readily accessible 2‐aryloxybenzaldehydes and 2‐(arylthio)benzaldehydes undergo a sequence of reactions leading to a wide variety of unsubstituted 9H‐xanthenes and thioxanthenes in high yields when heated with a Lewis acid in diisopropyl ether. This reductive cyclization method is compatible with several important functional groups. The method...

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