Highly Stereoselective Intramolecular Carbofluorination of Internal α,β-Ynones Promoted by Selectfluor

Photocatalytic Three-Component Synthesis of 3-Heteroarylbicyclo[1.1.1]pentane-1-acetates

Herein, we report a visible-light-induced three-component reaction involving [1.1.1]propellane, diazoates, and various heterocycles for the synthesis of 3-heteroarylbicyclo[1.1.1]pentane-1-acetates. Throughout this reaction, the radicals generated from diazoate species react with [1.1.1]propellane in an addition reaction to form bicyclo[1.1.1]pentane (BCP) radicals that subsequently react with heterocycles, leading to the formation of 1,3-disubstituted BCP acetates. Notably, this methodology exhibits excellent functional group compatibility, high atom economy, and mild reaction conditions, thus facilitating suitable synthetic access to 1,3-disubstituted BCP acetates.

Synthesis of C3-halo substituted bicyclo[1.1.1]pentylamines via halosulfoamidation of [1.1.1]propellane with sodium hypohalites and sulfonamides

Herein, we report a catalyst-free synthesis of C3-halo substituted bicyclo[1.1.1]pentylamines under mild conditions. The reaction involves the use of sodium hypohalites and sulfonamides to generate N-halosulfonamides in situ, which subsequently undergo radical addition with [1.1.1]propellane to yield the desired products with suitable functional group tolerance.

Cu-catalyzed cascade difluoroalkylation/5-endo cyclization/β-fluorine cleavage of ynones

A copper-catalyzed, redox-neutral cascade difluoroalkylation/5-endo annulation/β-fluorine cleavage of ynones is developed, providing a direct and stereoselective method to access synthetically important α-monofluoroalkenyl cyclopentanones. Mechanistic studies suggest an unprecedented Cu^II-assisted β-fluorine fragmentation, which may be valuable for the challenging but important C-F bond activation. Moreover, the in situ generated difluorocarbene was found to serve as an effective reductant for the regeneration of copper(I) catalyst, thus avoiding the addition of external reductants.

Fluorohydroxylation and Hydration Reactions of para-Quinone Methides Promoted by Selectfluor

Selectfluor-promoted vicinal fluorohydroxylation and hydration reaction of para-quinone methides (p-QMs) were described, affording vicinal fluorohydrins and ketone/ether products in high yields. The hydration products were highly controlled by the electronic properties of substituents in the aromatic ring, and simultaneously, the amount of Selectfluor was completely different during the synthesis of ketone/ether products. This reaction also represents the first fluorohydroxylation of p-QMs, and the wide range of p-QMs makes the vicinal fluorohydroxylation of great significance.

Synthesis of Imidized Cyclobutene Derivatives by Strain Release of [1.1.1]Propellane

Herein, we report the metal-free synthesis of imidized methylene cyclobutane derivatives via a strain-release driven addition reaction of [1.1.1]propellane. Using this strategy, the methylene cyclobutyl cation intermediate generated by protonation of [1.1.1]propellane was found to be trapped by nitriles to form a nitrilium ion intermediate, which subsequently reacted with carboxylic acids to produce imidized methylene cyclobutene derivatives via a Mumm-type rearrangement.

A Straightforward Approach to Fluorinated Pyrimido[1,2-b]indazole Derivatives via Metal/Additive-Free Annulation with Enaminones, 3-Aminoindazoles, and Selectfluor

A novel and efficient three-component reaction with two C-N bonds and one C-F bond formation has been reported, which provides a straightforward route to a variety of fluorinated pyrimido[1,2-b]indazole derivatives. This transformation has the advantage of excellent functional group compatibility, including aliphatic and aromatic substituents enaminones. Moreover, metal and additives are not necessary for this reaction, which is of great significance for the synthesis and application of fluorinated heterocycles.

Synthesis of Tetrasubstituted Alkenyl Nitriles via Cyanocarbene Addition of [1.1.1]Propellane

Herein, we report the metal-free synthesis of methylenecyclobutane containing tetrasubstituted alkenyl nitriles via a strain-release driven addition reaction of [1.1.1]propellane under mild conditions. Using this strategy, TMSN3 was shown to...