Regio- and Stereoselective Hydrochlorination/Cyclization of 1,n-Enynes by FeCl3 Catalysis

Electrochemical Oxidative Dibrominative Cyclization of 1,n-Enynes with Hypervalent Iodoarene Intermediates Utilizing Recyclable Bromine Ionic Liquids

An electrochemical approach with iodoarene as a mediator using recyclable ionic liquids to achieve dibromonative cyclization of 1,n-enynes has been reported. With recyclable bromine sources, in situ generation of iodine(III) compounds through electrochemical oxidation to achieve cyclization, a variety of heterocyclic frameworks containing both vinyl and alkyl bromide groups had been obtained in high yields with good selectivity.

Electrochemical Dichlorinative Cyclization of 1,n-Enynes by 4-Iodotoluene Catalysis

An electrochemical approach for the indirect oxidative generation of hypervalent iodoarene as a reaction catalyst has been reported. The reaction proceeds first from the generation of active Cl species by electro-oxidation, followed by oxidative transfer to generate ArICl2, which subsequently reacts with enynes to achieve cyclization. This protocol provides a simple and green method for accessing dichlorinative cyclization products in high yields with good selectivity.

Cs2CO3 Promoted [4 + 2] Cycloaddition of 1,6-Enynes: An Approach to Tetrahydro-1H-benzo-f-isoindole Isomers

A Cs2CO3-promoted [4 + 2] cycloaddition of 1,6-enynes under mild reaction conditions has been developed. This protocol provides a facile approach to a series of tetrahydro-1H-benzo[f]isoindole isomerized products promoted by Cs2CO3 with moderate to high yields. By simply switching the reaction solvent and controlling the reaction time, two isomerization products could be obtained, both with good selectivity.

Metal-free radical bicyclization/chloroalkylarylation of 1,6-enynes with chloroalkanes

Free radical initiated bicyclization of 1,6-enynes with chloralkanes, is achieved via selective activation of the C(sp3)-H bond of the chloralkane, resulting in diverse polychlorinated/chlorinated polyheterocycles. Two kinds of transformations and a scaled-up experiment were performed to test the synthetic importance of the organic chlorides. Finally, a range of radical inhibition operations and radical clock tests were explored to support the reaction process.

Highly effective and selective FeBr3-promoted deuterium bromination/cyclization of 1,n-enynes

A highly effective and selective FeBr3-promoted deuterium bromination/cyclization of 1,n-enynes is reported. On the one hand, the Lewis acid FeBr3 as a catalyst promotes cyclization of 1,n-enynes to afford deuterium heterocyclic frameworks with high efficiency. On the other hand, FeBr3 serves as the bromine source (with D2O as the deuterium source) to promote the formation of the desired deuterated pyrrole derivatives containing alkenyl bromide groups. This protocol provides an effective pathway to afford deuterated alkenyl brominative compounds as (Z)-isomers with high yields and selectivity, offering a new method for introducing 2H into organic compounds.

Interrupted Furan-Yne Cyclization: Access to Unsaturated Dicarbonyl Compounds and Their Subsequent Transformation into Functionalized Pyridazines

The key carbenoid intermediate of transition-metal-catalyzed furan-yne cyclization in Hashmi phenol synthesis could be efficiently intercepted with water under the developed reaction conditions in order to provide access to functionalized unsaturated dicarbonyl compounds that might serve as convenient precursors for the straightforward synthesis of annulated pyridazines.

Nucleophilic Allylation of Acylsilanes in Water: An Effective Alternative to Functionalized Tertiary α-Silylalcohols

A nucleophilic allylation of acylsilanes in water was developed, generating versatile functionalized tertiary α-silyl alcohols in high yields. With the assistance of hydrogen bonding, a reaction model of less reactive acylsilane was achieved. Unlike the conventional strategy, transition metals and an additional Lewis acid catalyst were not required, and rate acceleration was observed in water.