Gold(I)‐Catalyzed Alkynylation of N,O‐Acetals: An Access to Alkynylated Saturated N‐heterocycles

A synthetic route for the preparation of alkynylated saturated N-heterocycles via a sequential combination of a Shono oxidation and a gold(I)-catalyzed alkynylation reaction has been developed. The electrochemical Shono oxidation allowed an efficient access to a variety of N,O-acetals via a direct C-H bond functionalization of cyclic amines. The reaction...

1d

Photoinduced Synthesis of Bis‐Sulfonyl γ‐Arylated Ketones via DMAP/DDQ‐Mediated Stereogenic Conjugated Addition of α‐Sulfonyl Chalcones with Benzylic Sulfones

The DMAP/DDQ–mediated stereochemical conjugated addition of sulfonyl chalcones and benzylic sulfones under photolytic irradiation produces diverse bis-sulfonyl γ-arylated ketones with three contiguous stereogenic centers in a yield of 79%–92%. Herein, a plausible mechanism is proposed and discussed.

1d

A Scalable Synthesis of Chiral Himbert Diene Ligands for Asymmetric Catalysis

Chiral dienes are important ligands in asymmetric catalysis but they are less accessible than other commonly used ligands such as chiral bisphosphines. Here, we show that intramolecular [4 + 2] cycloaddition of a simply attained chiral allenecarboxanilide readily affords pseudoenantiomeric bicyclo[2.2.2]octa-2,5-dienes containing an alkenyl bromide,...

1d

Site Selective Concerted Nucleophilic Aromatic Substitutions of Azole‐Ligated Diaryliodonium Salts

Diaryliodonium salts are established electrophilic arylation reagents both in transition metal-catalyzed and transition metal-free reaction methods. Herein we present the application of azole-stabilized diaryliodonium salts with additional thiophen-2-yl-ligands as substrates for metal-free nucleophilic arylations. Besides their synthesis, we demonstrate...

1d

Synthesis of Linear Enamides and Enecarbamates via Photoredox Acceptorless Dehydrogenation

In recent years, several methods for the direct desaturation of aliphatic compounds have been developed, facilitated by the unique combination of photoredox and transition-metal catalysis. Hereby, alkenes as valuable molecules for synthesis can be prepared in an atom- and energy-efficient fashion. We present a dehydrogenative dual catalytic system that...

1d

Nickel‐Catalyzed Hydrocyanation of Terminal Allenes: Regio‐ and Enantioselective Access towards Branched Allylic Nitriles

A highly branched regioselective nickel(0)-catalyzed hydrocyanation of mono- and 1,1-disubstituted allenes as well as an asymmetric hydrocyanation of 1,1-disubstituted allenes is reported herein, giving access to branched tertiary and quaternary β,γ-allylic nitriles. For the regioselective hydrocyanation of terminal allenes, a nickel(0)/Biphephos catalytic...

1d

Visible‐Light‐Induced Photoredox Dehydrative Coupling/Cyclization of N‐Arylacrylamides with Hydroxyketones

A mild visible-light induced 4CzIPN/H+ photoredox system has been developed that enables hydroxyketones for the first time serving as a carbon radical precursor via formal C-O bond cleavage. This process was successfully exploited in the coupling/cyclization reaction of N-arylacrylamides and thereby provided a sustainable and efficient access to acyl...

2d

Electrochemical Hydroalkylation of Quinoxalin‐2(1H)‐ones with Alkyl Halides

Abstract We reported herein an electrochemically reductive alkylation, allylation and propargylation of quinoxalin-2(1H)-ones with haloalkanes. In an undivided cell, treatment of quinoxalin-2(1H)-ones and alkyl halides with constant current, a wide range of 3-alkylated-3,4-dihydroquinoxalin-2(1H)-one and its derivatives can be isolated in 25–87% yields.

3d

Visible‐light Induced Cerium‐catalyzed N‐Demethylation of N‐Methyl Amides under Air Conditions

Abstract A visible-light induced cerium-catalyzed N-demethylation of N-methyl amides under air atmosphere to the corresponding of N-demethylated amides is presented. Upon irradiation the excited states of [CeIVCln]2− are able to activate N-methyl amides. This reaction provides a methodology to cleave the C−N bond of amides under air conditions.

3d

Stereoselective Three‐Component Construction of Conjugated 1,3‐Dienes via Palladium‐Catalyzed Alkene/Allene/Carbenoid Insertion Cascade

Abstract A three component construction of conjugated 1,3-dienes bearing oxindoles or isoquinolinediones from alkenylated aryl iodides, allenes and diazo compounds via a palladium catalyzed sequential alkene/allene/carbenoid insertion reaction was developed. Three C−C bonds were formed in high order, offering access to multi-substituted dienes in high...

3d