Synthesis and Antiproliferative Evaluation of 2-Deoxy-N-glycosylbenzotriazoles/imidazoles

A series of 2-deoxy-2-iodo-α-d-mannopyranosylbenzotriazoles was synthesized using the benzyl, 4,6-benzylidene and acetyl protected D-glucal in the presence of N-iodosuccinimide (NIS). Subsequent removal of the iodine at the C-2 position using tributyltin hydride under free radical conditions afforded the 2-deoxy-α-d-glucopyranosylbenzotriazoles in moderate to high yields. This method was extended to the preparation of substituted 2-deoxy-β-d-glucopyranosylimidazoles as well. The stereoselectivity of the addition reaction and the effect of the protecting group and temperature on anomer distribution of the benzotriazole series were also investigated. The anticancer properties of the newly synthesized compounds were evaluated in a series of viability studies using HeLa (human cervical adenocarcinoma), human breast and lung cancer cell lines. The N-[3,4,6-tri-O-benzyl-2-deoxy-α-d-glucopyranosyl]-1H-benzotriazole and the N-[3,4,6-tri-O-acetyl-2-deoxy-α-d-glucopyranosyl]-2H-benzotriazole were found to be the most potent cancer cell inhibitors at 20 µM concentrations across all four cell lines.

Aminoalkyl radicals as halogen-atom transfer agents for activation of alkyl and aryl halides

Organic halides are important building blocks in synthesis, but their use in (photo)redox chemistry is limited by their low reduction potentials. Halogen-atom transfer remains the most reliable approach to exploit these substrates in radical processes despite its requirement for hazardous reagents and initiators such as tributyltin hydride. In this study, we demonstrate that α-aminoalkyl radicals, easily accessible from simple amines, promote the homolytic activation of carbon-halogen bonds with a reactivity profile mirroring that of classical tin radicals. This strategy conveniently engages alkyl and aryl halides in a wide range of redox transformations to construct sp3-sp3, sp3-sp2, and sp2-sp2 carbon-carbon bonds under mild conditions with high chemoselectivity.

Expedient synthesis of 3-hydroxypyrrolesviaBu3SnH-triggered ionic 5-exo-trig-cyclization of 5-chloro-3-azamuconoate derivatives

An unprecedented application of tributyltin hydride as a reagent for reductive ionic 1,5-cyclization of 3-azamuconoates into variously substituted 3-hydroxy-1H-pyrroles is described.

A Ru(iii) – catalyzed α-cross-coupling aldol type addition reaction of activated olefins with isatins

A α-cross-coupling aldol type addition reaction activated olefins with isatins has been described in the presence of ruthenium(iii) chloride and tributyltin hydride (TBTH) at room temperature.

The stereoselectivities of tributyltin hydride-mediated reductions of 5-bromo-d-glucuronides to l-iduronides are dependent on the anomeric substituent: syntheses and DFT calculations

Reduction of a 5-C-bromo-d-glucuronyl β-fluoride with tributyltin hydride gives exclusively the l-ido product. The selectivity is traced to a transition state gauche effect and an Sn–F interaction.

Functionalised 1-Alkynylarsines: Synthesis, Characterisation, and Attempts of Rearrangement into Functionalised Arsaalkynes

Functionalised 1-alkynylarsines were synthesised by reaction of the corresponding 1-alkynyltributylstannane on arsenic trichloride followed by chemoselective reduction of the formed 1-alkynyldichloroarsine by tributyltin hydride in the presence of small amounts of a radical inhibitor. Rearrangements of these compounds into the corresponding arsaalkynes were attempted.