Asymmetric Hetero-Diels–Alder Reaction of Danishefsky’s Dienes with α‑Carbonyl Esters Catalyzed by an Indium(III)–PyBox Complex

An efficient catalytic enantioselective hetero-Diels–Alder reaction of Danishefsky’s dienes with α-carbonyl esters using a chiral In(III)–pybox complex has been demonstrated. This protocol offers several advantages, including mild reaction conditions, relatively low catalyst loading, and good to excellent enantioselectivities. Furthermore, the absolute configurations of the new alkynyl-containing products were determined by CD spectra in combination with TD-DFT calculations

Iron-Catalyzed Cascade Carbochloromethylation of Activated Alkenes: Highly Efficient Access to Chloro-Containing Oxindoles

An iron-catalyzed carbodi- and trichloromethylation of activated alkenes with readily available dichloro- and tetrachloromethane has been developed. A diaryliodonium salt is used as an efficient oxidant in this transformation. This reaction tolerates a variety of functional groups and allows for a highly efficient synthesis of various chloro-containing oxindoles

Copper- and Cobalt-Catalyzed Direct Coupling of sp³ α‑Carbon of Alcohols with Alkenes and Hydroperoxides

A zerovalent copper- and cobalt-catalyzed direct coupling of the sp³ α-carbon of alcohols with alkenes and hydroperoxides was developed in which the hydroperoxides acted as radical initiator and then coupling partner. 1,3-Enynes and vinylarenes underwent alkylation–peroxidation to give β-peroxy alcohols and β-hydroxyketones correspondingly with excellent functional group tolerance. The resulting β-peroxy alcohols could be further transformed into β-hydroxy­ynones and propargylic 1,3-diols

Oxidant-Free Rh(III)-Catalyzed Direct C–H Olefination of Arenes with Allyl Acetates

Rh(III)-catalyzed direct olefination of arenes with allyl acetate <i>via</i> C–H bond activation is described using <i>N,N</i>-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of <i>trans</i>-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C–H olefination

Divergent Functionalization of Indoles with Acryloyl Silanes via Rhodium-Catalyzed C–H Activation

A protocol enabled by rhodium-catalyzed C–H functionalization of indoles with acryloyl silanes was developed, providing a convenient and highly effective method for the synthesis of functionalized acylsilane derivatives. By tuning the reaction condition, this C–H-activation-initiated reaction proceeds divergently with acryloyl silianes to selectively afford alkylation or alkenylation products via hydroarylation or oxidative cross-coupling, respectively. The mild reaction conditions employed in both cases enable the tolerance of a wide scope of functionalities as well as high reaction efficiency. Furthermore, polycyclic indole derivatives were easily accessed from 2-alkenylation products through a visible-light-induced reaction cascade

Transition-Metal-Free Synthesis of Substituted Pyridines via Ring Expansion of 2‑Allyl‑2<i>H-</i>azirines

A new strategy to open the 2-allyl-2<i>H</i>-azirines by 1,8-diazabicyclo[5.4.0]­undec-7-ene (DBU) promotion in metal-free conditions affording 1-azatrienes that <i>in situ</i> electrocyclize to the pyridines in good to excellent yields is reported. The reaction displays a broad substrate scope and good tolerance to a variety of substituents including aryl, alkyl, and heterocyclic groups. In addition, one-pot synthesis of pyridines from oximes via <i>in situ</i> formation of 2<i>H</i>-azirines was achieved

C_sp³–C_sp³ Bond Cleavage in the Palladium-Catalyzed Aminohydroxylation of Allylic Hydrazones Using Atmospheric Oxygen as the Sole Oxidant

A C–C bond cleavage was observed in the palladium-catalyzed aminohydroxylation of allylic hydrazones, using atmospheric oxygen as the sole oxidant. This reaction could also proceed in a one-pot manner, starting from keto-alkene compounds and phenylhydrazine

Chelation-Assisted Rhodium-Catalyzed Direct Amidation with Amidobenziodoxolones: C(sp²)–H, C(sp³)–H, and Late-Stage Functionalizations

Air-stable and convenient amidobenziodoxolones as an amidating reagent were disclosed to enable direct amidation on a wide range of C­(sp²)–H bonds of (hetero)­arenes and alkenes, as well as unactivated C­(sp³)–H bonds under Rh^III catalysis. The approach to access 49 examples of structurally diverse amides is featured by mild conditions, complete chemoselectivity and regioselectivity, broad substrate scope (not limited to strongly heterocyclic coordinating groups), and tolerance of valuable functional substituents, such as unprotected amine and hydroxyl groups. The synthetic applicability of this protocol is also demonstrated by late-stage functionalization of biologically important scaffolds

Palladium-Catalyzed Intermolecular Oxyarylation of Vinylacetates with Retention of an Alkenyl Moiety

Palladium-catalyzed intermolecular oxyarylation reaction of vinylacetates with retention of the double bond in the final product is developed. Under the optimized reaction conditions, the desired products of multisubstituted vinylesters could be obtained in moderate to high yields

Expedient Synthesis of Pyrroloquinolinones by Rh-Catalyzed Annulation of <i>N</i>‑Carbamoyl Indolines with Alkynes through a Directed C–H Functionalization/C–N Cleavage Sequence

A Rh-catalyzed redox-neutral C–H functionalization of <i>N</i>-carbamoyl indolines with various internal alkynes has been developed. The reaction, which involves the sequential cleavage of the C–H bond of the indoline at the C7-position and the C–N bond of the urea motif, provides a divergent protocol to rapidly assemble fused-ring pyrrolo­quinolinone analogues by using a direct alkenylation/annulation strategy with high efficiency and selectivity