Exploring the Reactivity of N-Alkynylated Sulfoximines: Acid-Catalyzed Cyclizations

Pd-Catalyzed double carbopalladation/syn-insertion cascade reactions toward medium-size sulfoximine heterocycles

With the assistance of Ac in sulfoximine as a protecting group (PG) and MeOH as a de-PG agent, Pd-catalyzed multicomponent reactions were developed to access indene-fused medium-size sulfoximine heterocycles. The reactions proceeded smoothly under exceptionally mild conditions to produce polyheterocyclic sulfoximines with regiospecificity and good functional group tolerance. A double carbopalladation/syn-insertion of triple bond sequences was proposed tothis transformation.

Copper-Catalyzed Chemodivergent Cyclization of N-(ortho-alkynyl)aryl-Pyrrole and Indoles

Herein, we described an efficient copper-catalyzed chemo-divergent tandem reaction of N-(ortho-alkynyl)aryl-pyrrole and (iso)indoles, delivering ring-fused N-heterocycles in good yields in an atom-economical manner. N-(ortho-alkynyl)aryl-pyrrole and indoles undergo the tandem cyclization/migration reaction, in which the group at 2-position was migrated to 3-position. In contrast, the dearomative cyclization of N-(ortho-alkynyl)aryl-isoindoles would occur to deliver the N-fused tetracyclic products efficiently.

Cyclization of ortho-ethynylbiaryls as an emerging versatile tool for the construction of polycyclic arenes

Cyclization and cycloisomerization of ortho-aryl(ethynyl)arenes provide an easy direct access to fused polycyclic aromatic carbo- and heterocycles. This methodology has demonstrated an impressive progress in the recent years. The goal of this review is to give a comprehensive outlook on the synthetic potential, scope, limitations, and mechanistic aspects of the cyclization reactions. The material is arranged according to the activation method that can be used to induce cyclization: pyrolysis, metal catalysis, electrophilic activation, radical induction, base catalysis. Particular attention is paid to the specificity of ortho-ethynylbiaryls with a heterocyclic central core.

The bibliography includes 257 references.

Pd/P/dba-Promoted cascade annulations to produce fused medium-sized sulfoximine polyheterocycles

The Pd-catalyzed multicomponent reactions of NH-sulfoximine, aryl iodide and norbornadiene (NBD) are reported to chemoselectively produce fused medium-sized sulfoximine polyheterocycles in good to excellent yields.

Metal-Free [2 + 2 + 2] Cycloaddition of Ynamide-Nitriles with Ynamides: A Highly Regio- and Chemoselective Synthesis of δ-Carboline Derivatives

A metal-free formal [2 + 2 + 2] cycloaddition of functionalized ynamide-nitriles with ynamides is disclosed which offers highly efficient access to polysubstituted δ-carboline derivatives under the mediation of TfOH. This strategy is highly regioselective and chemoselective and displays mild conditions, high yields, and efficiency (within 1 min) in addition to substrates scopes (56 examples).

Metal-Free Formal Inverse-Electron-Demand Diels-Alder Reaction of 1,2-Diazines with Ynamides

A highly effective metal-free formal inverse-electron-demand Diels-Alder reaction of 1,2-diazines with ynamides has been developed. This catalytic protocol is more environmentally friendly and allows for the construction of 2-aminonaphthalenes and 2-aminoanthracenes from 1,2-diazines and ynamides in good to high yields with wide diversity and functional group tolerance.

Rhodium(III)-Catalyzed C-H Alkynylation of N-Methylsulfoximines

A rhodium(III)-catalyzed direct C-H alkynylation of a wide range of N-methylsulfoximines with (bromoethynyl)triisopropylsilane has been developed. This protocol is compatible with both (S,S)-diaryl sulfoximines and (S,S)-alkyl aryl sulfoximines, and shows mild conditions, and good functional group tolerance. The synthetic utility of this method has been demonstrated by subsequent various transformations of the products.

Pd/Norbornene Collaborative Catalysis on the Divergent Preparation of Heterocyclic Sulfoximine Frameworks

Pd/Norbornene cocatalyzed tandem C-H activation/annulation reactions of free NH-sulfoximines with aryl iodides to produce diverse polyheterocyclic sulfoximines in highly chemoselective models are reported. The reaction tolerated a broad range of functional groups under external oxidant-free conditions. The preliminary mechanistic studies using density functional theory (DFT) calculations highlighted the key role of a Pd^IV intermediate.

Synthesis of fully-substituted 1,2,3-triazoles via copper(i)-catalyzed three-component coupling of sulfoximines, alkynes and azides

A copper(i)-catalyzed three-component reaction of sulfoximines, alkynes and azides is described, affording a variety of 1,2,3-triazolyl-5-sulfoximines in moderate to good yields.

Synthesis of pyrrolo[1,2-a]naphthyridines by Lewis acid mediated cycloisomerization

Functionalized pyrrolo[1,2-a]naphthyridines were synthesized by application of PtCl₂ and Bi(OTf)₃ as simple Lewis acids in a cycloisomerization reaction.