Direct Diazoarylation of [1.1.1]Propellane with Arenediazonium Salts: A Modular Assembly of Arylated Diazo Bicyclo[1.1.1]pentanes.

A mild and concise diazoarylation of [1.1.1]propellane is described, which provides a modular approach to arylated diazo bicyclopentanes (BCPs).

Photocatalyzed 1,3-Bromodifluoroallylation of [1.1.1]Propellane with α-Trifluoromethylalkenes and KBr Salts.

Herein we unveil a visible-light-driven transition-metal-free 1,3-bromodifluoroallylation of [1.1.1]propellane.

Umpolung Difunctionalization of Carbonyls via Visible-Light Photoredox Catalytic Radical-Carbanion Relay.

The combination of photoredox catalysis with the Wolff-Kishner (WK) reaction allows the difunctionalization of carbonyl groups by a radical-carbanion relay sequence (photo-Wolff-Kishner reaction). Photoredox initiated radical addition to -sulfonylhydrazones yields α-functionalized carbanions following the WK-type mechanism. With sulfur-centered radicals, the carbanions are further functionalized by reaction with electrophiles including CO and aldehydes, whereas CF radical addition furnishes a wide range of -difluoroalkenes through β-fluoride elimination of the generated α-CF carbanions.

Synthesis of Polysubstituted Pyrroles through a Formal [4 + 1] Cycloaddition/E1cb Elimination/Aromatization Sequence of Sulfur Ylides and α,β-Unsaturated Imines.

A reaction sequence comprising a formal [4 + 1] cycloaddition, an E1cb elimination, and an aromatization process is described in this work. By doing so, polysubstituted pyrroles were achieved from easily available chemicals, sulfur ylides, and α,β-unsaturated imines. This protocol features mild conditions, high efficiency, and wide substrate scopes.

Formal [3 + 2] Cycloadditions via Indole Activation: A Route to Pyrroloindolines and Furoindolines.

Here, we describe a novel [3 + 2] cycloaddition of 3-substituted indoles with vinyl aziridines and vinyl epoxides that provides a straightforward approach to pyrroloindolines and furoindolines bearing vinyl groups (up to 96% yield and 9:1 dr). In contrary to previous reports involving Lewis acid activation, this work reports successful reactions based on the activation of indole using t-BuOK and BEt (triethylborane), thereby preserving the free N-H group on indoles. In addition, a gram-scale reaction and a ring-closing metatheis reaction are performed to provide good demonstrations of the synthetic utility of this approach.

A Copper-Catalyzed Decarboxylative Amination/Hydroamination Sequence: Switchable Synthesis of Functionalized Indoles.

A copper-catalyzed decarboxylative amination/hydroamination sequence of propargylic carbamates with various nucleophiles is described for the first time. It features an earth-abundant metal catalyst, mild reaction conditions, and high efficiency. Further treatments of the resultant key intermediates using an acid or a base in one pot enable the controllable and divergent synthesis of two types of functionalized indoles.

Highly Stereoselective [3+2] Cycloadditions of Chiral Palladium-Containing N(1) -1,3-Dipoles: A Divergent Approach to Enantioenriched Spirooxindoles.

A catalytic asymmetric [3+2] cycloaddition reaction of chiral palladium-containing N(1) -1,3-dipoles with methyleneindolinones has been successfully developed. The reaction allows an efficient construction of 3,3'-pyrrolinyl spirooxindoles with high yields and excellent stereoselectivities (up to 93 % yield, 19:1 d.r.