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Allyltrimethylsilane inspired allylation of acetals, ketals, aldehydes, and ketones comprises one of the most viable, significant and graceful methods for the formation of carbon–carbon bonds leading to stereochemical transformation.

N‐bromosuccinimide (NBS)‐mediated one‐pot, green, efficient and practical synthesis of substituted imidazoles and quinoxalines has been achieved by the reaction of styrenes with N‐arylbenzamidines and o‐phenylenediamines, respectively, in a water:1,4‐dioxane mixture. The reaction involves formation of an α‐bromo ketone as an intermediate in the presence of NBS and water, followed by condensation with the N‐arylbenzamidine and o‐phenylenediamine. Use of an inexpensive NBS as a bromine source as well as an oxidant, water as a solvent and readily available starting materials makes this protocol environmentally benign and economically viable. Substituted imidazoles and quinoxalines were obtained in good to excellent yields with wide functional group compatibility.magnified image

A metal‐free, adorable, cascade protocol for the synthesis of pyrrolo[1,2‐a]quinoxalines at room temperature using benzylamine derivatives and 1‐(2‐aminoaryl)pyrrole has been performed. This synthetic protocol involves oxidation of benzylamine derivatives into respective aldehydes followed by condensation with 1‐(2‐aminoaryl)pyrrole in PEG‐400 as a green and reusable solvent using K2S2O8 as an oxidant. The transition metal free as well as ligand free synthesis along with broad substrate scope, wide functional group tolerance and good to excellent yield of products makes it environmentally and economically viable.

A one‐pot simple, efficient and practically viable protocol for the synthesis of substituted 1,3,5‐triazines has been reported from arylacetic acids and benzamidine hydrochloride. In addition, we demonstrated first transition metal‐free conversion of phenylacetic acid to benzaldehyde which on condensation with two equivalents of benzamidine hydrochloride offered 2,4,6‐trisubstituted 1,3,5‐triazines. This protocol is environmentally benign and economically viable which makes it feasible for gram scale synthesis.

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A convenient and effective FeCl 3 catalyzed one-pot three component protocol for the synthesis of 1,2,4-trisubstituted imidazoles from arylacetic acids, N-arylbenzamidines and nitromethane via simultaneous CÀH and NÀH bond activation has been developed. The reaction involves CÀH activation of arylacetic acid to form aromatic aldehyde which on condensation with N-arylbenzamidine gives azadiene. Nitromethane on Michael addition with azadiene produces ring annulated intermediate which upon subsequent cyclization-elimination sequence offers imidazole. The process utilizes readily available arylacetic acids and inexpensive catalyst. This user friendly protocol provided 1,2,4-trisubstituted imidazoles in moderate to good yields with high functional group tolerance and ample substrate scope.[a] S.