FeCl3-Promoted Facile Synthesis of Multiply Arylated Nicotinonitriles

Many biologically active nicotinonitriles have been reported to date. Consequently, the development of synthetic methods for multiply arylated/alkylated nicotinonitriles remains a sought-after field of research. In the present work, a new synthetic strategy for multi-substituted nicotinonitriles was provided. A FeCl3-promoted condensation-cyclization reaction of an enamino nitrile and α,β-unsaturated ketones efficiently proceeded with a wide range of substrates. It is noteworthy that this method facilitated the access to fully- and differently substituted nicotinonitriles including tetra-arylated nicotinonitriles in only three steps. Using the functionality of the cyano group, the copper-catalyzed annulation reaction of the nicotinonitrile was achieved to yield benzo[c][2,7]naphthyridin-5(6H)-one.

Asymmetric Synthesis of Isochromanone Derivatives via Trapping Carboxylic Oxonium Ylides and Aldol Cascade

An efficient asymmetric synthesis of isochromanone derivatives was realized through Z-selective-1,3-OH insertion/aldol cyclization reaction involving acyclic carboxylic oxonium ylides. The combination of achiral dirhodium salts and chiral N,N’-dioxide-metal complexes, along...

Synthesis of 2-trifluoromethyl chromenes via double carbonyl-ene reaction

A new protocol for the synthesis of diversely substituted 2-trifluoromethyl chromenes from the cyclization reaction of o-isopropenylphenols with trifluoroacetic anhydride has been developed, which proceeds via sequential trifluoroacetylation and double...

Rhodium-catalyzed coupling-cyclization reaction of isocyanides and 2-azidophenyloxyacrylates: synthesis of N-(3-substituted benzo[d]oxazol-2(3H)-ylidene)amines and dihydrobenzo[d]oxazoles

A rhodium-catalyzed coupling cyclization of isocyanides with 2-azidophenyloxyacrylates has been developed for the first time. This reaction allows divergent syntheses of two significant N-heterocycles, five-membered N-(3-substituted benzo[d]oxazol-2(3H)-ylidene)amines and dihydrobenzo[d]oxazoles, from...

Cobalt-Catalyzed Cyclization of 2-Bromobenzamides with Carbodiimides: A New Route for the Synthesis of 3-(Imino)isoindolin-1-ones

A novel synthetic pathway to approach 3-(imino)isoindolin-1-ones by the Co-catalyzed cyclization reaction of 2-bromobenzamides with carbodiimides has been developed. This catalytic reaction can tolerate a variety of substituents and provide corresponding products in moderate yields for most cases. According to the literature, the reaction mechanism is proposed through the formation of a five-membered aza-cobalacycle complex, which carries out the following reaction subsequence, including nucleophilic addition and substitution, to furnish the desired structures.

2,2′-(1,4-Phenylene)bis(7-nitro-1H-benzimidazole 3-oxide)

Bis(benzimidazol-2-yl-3-oxide)benzene derivatives have potential applications as energetic or photoactive materials. By using a two-step one-pot approach employing microwave heating as a tool, 2,2′-(1,4-phenylene)bis(7-nitro-1H-benzimidazole 3-oxide) (1) has been prepared in 94% yield. In the first step an SNAr reaction is performed using p-xylylenediamine as the central building block. Without isolating the intermediate, a base-mediated cyclization reaction follows in the second step. The product was isolated in analytically pure form by means of a pH-controlled precipitation.