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• 109-72-8 n-butyllithium 

Relevant academic research and scientific papers

Synthesis of 2-Acylselenophenes via Iodine-Promoted Nucleophilic Cyclization of [2-(Butylselanyl)phenyl]-propynols

We describe the synthesis of [2-(butylselanyl)phenyl]propynols and their application as substrates in intramolecular iodine-promoted nucleophilic cyclization reactions for the preparation of 2-acylselenophenes. [2-(Butylselanyl)phenyl]propynols were prepared by nucleophilic aromatic substitution reactions of 2-halobenzaldehydes with lithium butylselenolate followed by alkynylation of the carbonyl function with lithium acetylides. Effects of solvent, temperature, reaction time and iodine amount on the efficiency of the cyclization reactions were investigated. The results demonstrated that the best yields of 2-acylselenophenes were obtained when iodine (1.1 equiv.) and ethanol (3 mL) at room temperature were applied to [2-(butylselanyl)phenyl]propynols. The utility of 2-acylselenophene derivatives was also studied through alkynylation of a carbonyl group to obtain the alkynol derivatives followed by an electrophilic cyclization reaction to give selenophene-fused aromatic compounds. The 2-acylselenophene was also applied as a substrate in cyanation reactions.

One-Pot Synthesis of 3-Halo-2-organochalcogenylbenzo[b]chalcogenophenes from 1-(2,2-Dibromovinyl)-2-organochalcogenylbenzenes

A transition-metal-free one-pot synthesis of 3-halo-2-organochalcogenylbenzo[b]chalcogenophenes has been developed using 1-(2-organochalcogenylethynyl)-2-butylchalcogenylbenzenes generated in situ from 1-(2,2-dibromovinyl)-2-organochalcogenylbenzenes and

Synthesis of benzo[b]chalcogenophenes fused to selenophenesviaintramolecular electrophilic cyclization of 1,3-diynes

We describe herein an alternative and transition-metal-free procedure for the access of benzo[b]chalcogenophenes fused to selenophenesviaintramolecular cyclization of 1,3-diynes. This efficient protocol involves a double cyclization of 1,3-diynyl chalcogen derivatives promoted by the electrophilic species of organoselenium generatedin situby the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone in acetonitrile as solvent in an open-flask at 80 °C. In this study, 15 selenophenes with broad substrate scope were prepared in moderate to excellent yields (55-98%) with short reaction times (0.5-3.0 h).

Iron-Promoted Tandem Cyclization of 1,3-Diynyl Chalcogen Derivatives with Diorganyl Dichalcogenides for the Synthesis of Benzo[b]furan-Fused Selenophenes

A double intramolecular 5-endo-dig cyclization of butyl[2-(phenylbuta-1,3-diynyl)phenyl]chalcogens has been employed in a selective preparation of benzo[b]chalcogenopheno[2,3-d]furans. Several reaction parameters were studied to determine the best reaction conditions and we observed that the reaction of butyl[2-(phenylbuta-1,3-diynyl)phenyl]chalcogens (0.25 mmol) with iron(III) chloride hexahydrate (2.0 equiv.) and diorganyl diselenides (1.75 equiv.) at reflux of dichloromethane was the most appropriate to give the products in 35–89% yields. These standard reaction conditions were compatible with many functional groups in the substrates, such as methyl, chlorine, fluorine, methoxy and heteroaryl. This protocol was also efficient for diorganyl diselenides but it was ineffective with diorganyl disulfides and ditellurides. In a competition among selenium, sulfur and oxygen nucleophiles we observed that the nucleophilicity and steric effects of the competing functional groups were determinant factors for the selectivity of the cyclization. The benzo[b]chalcogenopheno[2,3-d]furans had absorptions in the UV region (300–350 nm range) with molar absorptivity coefficient values ascribed to spin and symmetry allowed π–π* electronic transitions. An emission located in the purple region (380–440 nm range), with a Stokes shift of between 65–100 nm, is probably associated to the charge transfer character of the excited state. (Figure presented.).