Boron trifluoride promoted reaction of benzenesulphenanilides with alkenes-arylaminosulphenylation of alkenes.

The addition of benzenesulphenanilides to alkenes in the presence of boron trifluoride provides a practicable synthetic procedure for the arylaminosulphenylation of alkenes.     

Boron trifluoride promoted reactions of n-haloelectrophiles with alkenes

N-Haloelectrophiles react with alkenes in the presence of boron rifluoride etherate to give halofluorides and N-halo adducts.     

Pechmann reaction promoted by boron trifluoride dihydrate

The Pechmann reaction of substituted phenols 1a-e with methyl acetoacetate (2) can be activated by boron trifluoride dihydrate (3) to give the corresponding 4-methyl- coumarin derivatives 4a-e in excellent yield (98-99 %).     

Boron trifluoride induced palladium-catalyzed cross-coupling reaction of 1-aryltriazenes with areneboronic acids

[reaction: see text] Aryltriazenes are directly coupled with areneboronic acids in the presence of a catalytic amount of Pd(2)(dba)(3) and P(tBu)(3) together with 1 equiv of BF(3).OEt(2) in DME to afford the corresponding biaryl products in up to 98% yield. A carbonylative cross-coupling reaction under a carbon monoxide atmosphere is also found to give the corresponding diaryl ketone with a similar catalyst system.     

A ring opening reaction of oxetanes with lithium acetylides promoted by boron trifluoride etherate

Several substituted oxetanes were treated with lithium acetylides in the presence of boron trifluoride etherate to give f-hydroxyacetylenes. The reaction conditions were varied and several synthetic features of the present reaction were revealed.     

Boron trifluoride facilitated transesterification of dioxaborolanes

The direct transesterification of dioxaborolanes (alkane-1,2-diol based boronate esters) was explored. Using BF₃·OEt₂, alkane-1,2-diol based mono- and bis-boronate esters (i.e., pinacol and ethylene glycol) have been converted quantitatively to either benzene-1,2-diol or alkane-1,3-diol based boronate esters. In the case of pinacol esters, esterification is facilitated by the accompanying pinacol rearrangement, thus shifting the reaction equilibrium.     

Zirconium-catalyzed reaction of terminal alkenes with triethylindium

Terminal alkenes (undec-1-ene, oct-1-ene, and allylbenzene) reacted with triethylindium in the presence of a catalytic amount of Cp₂ZrCl₂ in hexane to give mixtures of three organoindium compounds whose hydrolysis in D₂O afforded 2-substituted 1,4-dideuterobutane containing minor amounts of 2-substituted 1- and 4-deuterobutanes.     

Palladium-induced electron-transfer reaction of difluorodiiodomethane with alkenes

The addition reaction of difluorodiiodomethane (1) with alkenes in the presence of PdCl2(PPh3)2 or Pd(PPh3)4 afforded the corresponding iododifluoromethylated compounds in excellent yield.     

Alumina supported potassium fluoride promoted reaction of nitroalkanes with electrophilic alkenes : synthesis of 4,5-dihydro furans and isoxazoline n-oxides

The reaction of secondary nitro alkanes 1 with α,β-unsaturated ketones 2 in the presence of alumina-supported potassium fluoride in acetonitrile gave 4,5-dihydrofurans 3 in high yields ; 1-nitropropane reacted with 2 to give a mixture of 4,5-dihydrofurans and furans. Nitroalkenes 17 reacted with nitroalkanes to give isoxazoline N-oxides 18 and 19 in good overall yields.     

Oxidation of alkenes with hydrogen peroxide, catalyzed by boron trifluoride. Synthesis of vicinal methoxyalkanols

In oxidation of alkenes with the BF₃-H₂O₂ system, boron trifluoride induces transfer of available oxygen from hydrogen peroxide, accompanied by the formation of epoxides. The oxidation in methanol occurs as a one-pot two-step process involving epoxidation of the C=C bond followed by opening of the oxirane ring, with the formation of methoxyalkanols.     

Aqueous-biphasic hydroformylation of higher alkenes promoted by alkylimidazolium salts

Aqueous-biphasic hydroformylation of higher alkenes (>C5) can be greatly accelerated by addition of 1-octyl-3-methylimidazolium bromide without affecting the phase separation and with good catalyst retention in the aqueous phase.     

Palladium-catalyzed direct cross-coupling reaction of glycals with activated alkenes

An efficient method for a Pd(OAc)(2)-catalyzed cross-coupling reaction of glycals with activated alkenes under mild conditions has been developed. This transformation provides an expedient synthetic method to C(2)-functionalized glycals, which are common structural building blocks in natural products and other biologically active compounds. The reaction scope includes different kinds of carbohydrates, protecting groups and substituents on alkene. Moderate to excellent yields and pure E configuration selectivity were obtained.     

Palladium-catalyzed reaction of phenyl fluoroalkanesulfonates with alkynes and alkenes

Palladium-catalyzed reaction of phenyl fluoroalkanesulfonates with alkynes and alkens under mild conditions gives the corresponding alkynyl and alkenyl substituted benzenes in good yields.     

Copper(II) carboxylate promoted intramolecular diamination of terminal alkenes: improved reaction conditions and expanded substrate scope

The copper(II) carboxylate promoted diamination reaction has been improved by the use of the organic soluble copper(II) neodecanoate [Cu(ND)2]. Cu(ND)2 allowed the less-polar solvent dichloroethane (DCE) to be used, and as a consequence, decomposition of less-reactive substrates could be avoided. High diastereoselectivity was observed in the synthesis of 2,5-disubstituted pyrrolidines. Ureas, bis(anilines), and alpha-amido pyrroles derived from 2-allylaniline could also participate in the diamination reaction.     

Novel fluoride transfer in the reaction of tricyclic epoxides with boron trifluoride

Reaction of the tricyclic epoxides ($\text{1a}$) and ($\text{1b}$) with boron trifluoride etherate leads to fluorohydrins ($\text{2a}$) and ($\text{2b}$) derived in the novel fluoride transfer, whereas ($\text{1c}$) undergoes isomerization to spiro ketone ($\text{3}$).     

Preparation of fluorolactones from the reaction of γ-ketoacids with diethylaminosulfur trifluoride

Levulinic acid and related γ-ketoacids react with diethylaminosulfur trifluoride to give γ-fluorobutyrolactones in good yield. The involvement of a bicyclic (3.2.1) mechanism is considered.     

(Fluoro)alkylation of alkenes promoted by photolysis of alkylzirconocenes

Difluoroalkylated compounds have important applications in pharmaceutical, agrochemical, and materials science. However, efficient methods to construct the alkylCF₂–alkyl bond are very limited, and the site-selective introduction of a difluoromethylene (CF₂) group into an aliphatic chain at the desired position remains challenging. Here, we report an unprecedented example of alkylzirconocene promoted difluoroalkylation of alkyl- and silyl-alkenes with a variety of unactivated difluoroalkyl iodides and bromides under the irradiation of visible light without a catalyst. The resulting difluoroalkylated compounds can serve as versatile synthons in organic synthesis. The reaction can also be applied to activated difluoroalkyl, trifluoromethyl, perfluoroalkyl, monofluoroalkyl, and nonfluorinated alkyl halides, providing a general method to controllably access fluorinated compounds. Preliminary mechanistic studies reveal that a single electron transfer (SET) pathway induced by a Zr(iii) species is involved in the reaction, in which the Zr(iii) species is generated by the photolysis of alkylzirconocene with blue light.

An unprecedented example of alkylzirconocene promoted difluoroalkylation of alkyl- and silyl-alkenes with a variety of fluoroalkyl and nonfluoroalkyl halides under the irradiation of visible light has been reported.