Thiazolium-Mediated Multicomponent Reactions: A Facile Synthesis of 3-Aminofuran Derivatives

NHC-catalysed annulation of enals to tethered dienones: efficient synthesis of bicyclic dienes

Homoenolates generated from α,β-unsaturated aldehydes using NHC catalysis underwent facile addition to dibenzylidene cyclohexanone to afford bicyclic cyclopentenes as single diastereomers.

Green method for the synthesis of highly substituted cyclohexa-1,3-diene, polyhydroindene, polyhydronaphthalene, isochromene, isothiochromene, and isoquinoline derivatives in ionic liquids

An efficient and green method for the synthesis of highly substituted cyclohexa-1,3-diene, polyhydroindene, polyhydronaphthalene, isochromene, isothiochromene, and isoquinoline derivatives has been developed. The synthesis was achieved by using a multicomponent procedure in ionic liquid media. The features of this procedure are characterized by the following: mild reaction conditions, high yields, one-pot procedures, operational simplicity, and environmentally benign conditions.

N-heterocyclic carbene catalyzed reaction of enals and 1,2-dicarbonyl compounds: stereoselective synthesis of spiro gamma-butyrolactones

[reaction: see text]. Nucleophilic heterocyclic carbene (NHC) catalyzed annulation of enals and cyclic 1,2-dicarbonyl compounds, opening a route to gamma-spirolactones, has been observed for the first time. The strategy works well with isatins, leading to spiroannulated oxindole derivatives. It is conceivable that the spiroannulation protocol reported herein will be applicable to the synthesis of important natural products that are endowed with a spiro gamma-butyrolactone motif, especially oxindoles and norsesquiterpenoids.

Facile Synthesis of Highly Substituted 3-Aminofurans from Thiazolium Salts, Aldehydes, and Dimethyl Acetylenedicarboxylate

[reaction: see text] A facile preparation of 3-aminofuran derivatives via multicomponent reactions of thiazole carbenes, aldehydes, and dimethyl acetylenedicarboxylate (DMAD) is reported. In this process, the thiazole carbenes, generated in situ from thiazolium salts, reacted with aldehydes and DMAD at -78 to 0 degree C in CH(2)Cl(2) to afford the substituted furans in moderate to good yields. Eight substituted thiazolium salts were employed as carbene precursors in the reaction. Besides aryl aldehydes, alpha,beta-unsaturated aldehydes, aliphatic aldehydes, and arenedial were also investigated and found to be applicable to this reaction.

One-Step Assembly of Functionalized γ-Butyrolactones from Benzoins or Benzaldehydes via an N-Heterocyclic Carbene-Mediated Tandem Reaction

We describe here a direct, efficient, one-step construction of gamma,gamma-difunctionalized gamma-butyrolactones from benzoins or benzaldehydes via a tandem reaction promoted by 1,3-dimethyl imidazolin-2-ylidene, an N-heterocyclic carbene (NHC). [reaction: see text]