58696-51-8

Upstream product

• 673-32-5 1-Phenylprop-1-yne 

Downstream Products

• 673-32-5 1-Phenylprop-1-yne 

Relevant academic research and scientific papers

Preparation of vincinal hetero 1,2-dihalo-olefins by using aqueous hydrohalic acid

An efficient simple method was developed to prepare hetero E-1,2-dihaloolefins from mono- or disubstituted alkynes, in which, NXS (X = Br, I) was utilized as the electrophilic reagents and aqueous hydrohalic acid as the nucleophile. Moreover, Z-type dihalogenation olefins could be obtained from the terminal silylacetylene.

TEMPO-Regulated Regio- and Stereoselective Cross-Dihalogenation with Dual Electrophilic X+ Reagents

A TEMPO catalyzed cross-dihalogenation reaction was established via redox-regulation of the otherwise complex system of dual electrophilic X+ reagents. Formally, the ICl, BrCl, I2 and Br2 were generated in-situ, which enabled high regio- or stereoselective access to a myriad of iodochlorination, bromochlorination and homo-dihalogenation products with a wide spectrum of functionalities. With its mild conditions and operational simplicity, this method could enable wide applications in organic synthesis, which was exemplified by divergent synthesis of two pharmaceuticals. Detailed mechanistic investigations via radical clock reaction, pinacol ring expansion and Hammett experiments were conducted, which confirmed the intermediacy of halonium ion. In addition, a dynamic catalytic model based on the versatile catalytic role of TEMPO was proposed to explain the selective outcomes.

Regio- and Stereoselective Synthesis of 1,2-Dihaloalkenes Using In-Situ-Generated ICl, IBr, BrCl, I2, and Br2

We describe a catalyst-free 1,2-trans-dihalogenation of alkynes with an unprecedented substrate scope and exclusive regio- and stereoselectivity. This versatile dihalogenation system—a combination of NX1S electrophile and alkali metal halide (MX2) in acetic acid—is applicable for diverse categories of alkynes (electron-rich or poor alkynes, internal and terminal alkynes, or heteroatoms such as O-, N-, S-substituted alkynes). The hydrogen bonding donor solvent acetic acid is essential for the in-situ generation of X1X2 electrophile, including ICl, IBr, BrCl, I2, and Br2. Haloalkenes are not only commonly found in biologically active natural products but also have been used extensively in cross-coupling reactions. More specifically, 1,2-dihaloalkenes are especially important synthons because of the presence of two synthetic handles that open a broad avenue to expeditiously generate multisubstituted alkenes. Dihalogenation of alkynes is a straightforward way to prepare 1,2-dihaloalkenes. However, existing alkyne dihalogenation methods either rely on the use of toxic reagents, such as IBr and ICl, lack regio- and stereoselectivity or have limited substrate scope. Thus, the development of a widely applicable and yet efficient alkyne dihalogenation method is still highly desired. Here, we have addressed the aforementioned issues based on an in-situ-generated dihalogenation of reagents, such as ICl and Ibr, by using the readily available N-halosuccinimide (NXS) and alkali metal halides as halogen sources. Our method offers an unprecedented substrate scope, the regio- and stereoselectivity for the synthesis of 1,2-dihaloalkenes. Our simple and mild conditions might find wild applications in the preparation of high-value building blocks for medicines and materials. Dihaloalkenes are important raw materials for pharmaceutical and chemical industries. However, existing preparation methods suffer from a limited substrate scope as well as poor regio- and stereoselectivity. Furthermore, these methods often necessitate highly toxic reagents, such as Cl2, ICl, and BrCl. Our environmentally friendly 1,2-trans-dihalogenation is based on easy-handling halide sources, such as alkali metal halides. What is more, our method offers an unprecedented substrate scope, the regio- and stereoselectivity for the synthesis of 1,2-dihaloalkenes.

Reaction of Alkynes with Iodine Monochloride Revisited

6-Exo-dig and/or 7-endo-dig iodocyclization reactions of functionalized acetylenic derivatives with ICl are disfavored in comparison with the corresponding electrophilic addition reactions providing regioselectively (E)-1-chloro-2-iodoethene derivatives. On the contrary, 6-endo-dig and 5-exo-dig iodocyclizations of methyl ynoates with ICl seem to be favored in comparison with the corresponding electrophilic addition reactions.

Regio- and stereospecific iodochlorination of alkenes and alkynes with polystyrene-[4-vinylpridinium dichloroiodate(I)]

Polystyrene-[4-vinylpyridinium dichloroiodate(I)] can be used for regio- and stereospecific iodochlorination of different alkenes and phenylsubstituted alkynes. In all cases the reaction followed the Markownikov type of regioselectivity and the addition p

Electrophilic Additions of Positive Iodine to Alkynes through an Iodonium Mechanism

Alkynes react with bis(pyridine)iodonium (I) tetrafluoroborate (1) and nucleophiles (CH3COOH, HCOOH, Cl-, pyridine, Br-, I-) to give 1,2 iodofunctionalized alkenes.The regiochemistry of the processes is in accordance with

Stereoselective Bifunctionalization of Alkynes by Means of the Mercury(II) Salt-Iodine Combination

The reaction of alkynes with iodine and mercury(II) salts (chloride, acetate, methanesulphonate, toluene-p-sulphonate, benzylsulphide, toluene-p-sulphinate, and thiocyanate) affords stereoselectively E-β-functionalized vinyl iodides resulting from the ionic addition of iodine and the mercury(II) salt anion.Unsymmetrical alkynes yield regiospecifically Markovnikov addition products.In the case of mercury(II) thiocyanate the reaction can be used also for the stereoselective preparation of E-1,2-dithiocyanatoalkenes.An ionic mechanism is proposed according to the observed regio- and stereochemistry.