Organocatalytic Direct <i>N</i>‑Acylation of Amides with Aldehydes under Oxidative Conditions

The direct oxidative <i>N</i>-acylation reaction of primary amides with aryl/α,β-unsaturated aldehydes was achieved in the presence of azolium salt <b>C3</b> and an inorganic base using 3,3′,5,5′-tetra-<i>tert</i>-butyldiphenoquinone as the oxidant, thus providing an efficient approach for the synthesis of three types of imide compounds including <i>N</i>-sulfonylcarboxamides, <i>N</i>-sulfinylcarboxamides, and dicarboxyimides in good yield

Crossover-Annulation/Oxygenation Approach to Functionalized Phenanthridines by Palladium–Copper Relay Catalysis

A tandem crossover-annulation and oxygenation process of conjugated enediyne-acids and <i>ortho</i>-alkynylanilines was achieved by palladium–copper relay catalysis under an oxygen atmosphere, giving access to the three-component assembly of 9-acylphenanthridine compounds

Pd-Catalyzed Branching Cyclizations of Enediyne-Imides toward Furo[2,3‑<i>b</i>]pyridines

The convergent synthesis of a class of enediyne-imides as well as their palladium-catalyzed branching cyclizations, which can be accomplished in two ways leading to a set of polysubstituted furo­[2,3-<i>b</i>]­pyridines upon using the <i>N</i>-tosyl carboxamide moiety as an <i>N</i>,<i>O</i>-bisnucleophile, are presented

Tuning of Copper-Catalyzed Multicomponent Reactions toward 3‑Functionalized Oxindoles

A tunable copper-catalyzed azide–alkyne cycloaddition (CuAAC)-initiated multicomponent reaction strategy for the construction of 3-functionalized indolin-2-ones is reported. Upon controlling the ring opening of four-membered <i>O</i>-heterocyclic intermediates, this unique method enables the divergent derivatization of <i>N</i>-protected isatins to give three-component (3-CR) and four-component (4-CR) adducts, respectively

Pd-Catalyzed Branching Cyclizations of Enediyne-Imides toward Furo[2,3‑<i>b</i>]pyridines

The convergent synthesis of a class of enediyne-imides as well as their palladium-catalyzed branching cyclizations, which can be accomplished in two ways leading to a set of polysubstituted furo­[2,3-<i>b</i>]­pyridines upon using the <i>N</i>-tosyl carboxamide moiety as an <i>N</i>,<i>O</i>-bisnucleophile, are presented

Coupling and Decoupling Approach Enables Palladium-Catalyzed Aerobic Bimolecular Carbocyclizations of Enediynes to 2,6-Diacylnaphthalenes

A formal palladium-catalyzed aerobic bimolecular carbocyclization reaction of (<i>Z</i>)-hexa-1,5-diyn-3-ene scaffolds has been successfully developed for the construction of 2,6-diacylnaphthalenes, wherein copper salts play a critical role in accomplishing the oxygenative homo- and hetero-dimerization processes of readily accessible enediyne–carboxylic acids and esters, respectively. The enediyne dimerization protocol provides a flexible and regiospecific approach to a variety of functionalized naphthalenes with up to six differentiated substituents in good yields by using a directing-group-assisted coupling and decoupling strategy. Mechanistic studies indicated that the two oxygen atoms being selectively incorporated into the crossover-annulation products of enediynecarboxylic acid and ester directly originate from atmospheric molecular oxygen and H₂O, respectively

Three-Component Assembly of Conjugated Enyne Scaffolds via <i>E</i>-Selective Olefination of Ynals

Benefited by the accessible ynamido–lithium intermediates <b>Ib</b> from a Cu-catalyzed azide–alkyne cycloaddition in the presence of stoichiometric amounts of LiOH, a mild and flexible three-component route to conjugated enyne scaffolds was successfully achieved via a formal <i>E</i>-selective olefination strategy

Three-Component Functionalized Dihydropyridine Synthesis via a Formal Inverse Electron-Demand Hetero-Diels–Alder Reaction

A mild three-component synthetic approach to versatile 2-amino-1,4-dihydropyridines from terminal alkynes, sulfonyl azides, and <i>N</i>-sulfonyl-1-aza-1,3-butadienes was successfully developed and relied on the in situ generation of metalated ynamide intermediates <b>Ib</b> to achieve a formal inverse electron-demand hetero-Diels–Alder reaction. Experimental results suggest that alkali metal cations (Li⁺ and Cs⁺ ions) might play a critical role to achieve the cycloaddition process

Copper-Catalyzed Tandem Reaction of Terminal Alkynes and Sulfonyl Azides for the Assembly of Substituted Aminotriazoles

A simple combination of CuI/LiO<i>t</i>Bu/DMF enables the tandem Huisgen [3 + 2] cycloaddition/amidation reaction of terminal alkynes and sulfonyl azides to 5-sulfamide-1-(<i>N</i>-sulfonyl)-1,2,3-triazoles <b>I</b>, which can undergo an alkylation/desulfonation sequence to deliver highly substituted aminotriazoles <b>II</b> by one-pot or one-pot, two-step procedures

Copper-Catalyzed Tandem Reaction of Terminal Alkynes and Sulfonyl Azides for the Assembly of Substituted Aminotriazoles

A simple combination of CuI/LiO<i>t</i>Bu/DMF enables the tandem Huisgen [3 + 2] cycloaddition/amidation reaction of terminal alkynes and sulfonyl azides to 5-sulfamide-1-(<i>N</i>-sulfonyl)-1,2,3-triazoles <b>I</b>, which can undergo an alkylation/desulfonation sequence to deliver highly substituted aminotriazoles <b>II</b> by one-pot or one-pot, two-step procedures