20657-43-6

Upstream product

• 82988-74-7 (2-chlorophenyl)diazomethane 
• 611-19-8 1-chloro-2-(chloromethyl)benzene 
• 25144-38-1 (E)-2,2'-dichlorostilbene 
• 1486-28-8 diphenyl(methyl)phosphine 
• 611-17-6 1-bromomethyl-2-chlorobenzene 
• 89-98-5 2-chloro-benzaldehyde 
• 18583-55-6 2-chlorobenzyl-triphenylphosphonium chloride 
• 1377975-11-5 2-chlorobenzylmethyldiphenylphosphonium bromide 
• 5293-77-6 1-chloro-2-(2'-chlorophenylethynyl)-benzene 
• 1334478-54-4 Br^(1-)*C₂₀H₁₆Cl₂N₃⁽¹⁺⁾ 
• 107135-19-3 N’-(2-chlorobenzylidene)-4-methylbenzenesulfonohydrazide 
• 62640-67-9 1-(2'-chlorobenzyl)triphenylphosphonium bromide 
• 91110-67-7 1-chloro-2-(phenylsulfonylmethyl)benzene 
• 77421-13-7 (2-chlorobenzyl)sulfonyl chloride 

Downstream Products

• 25144-38-1 (E)-2,2'-dichlorostilbene 

Relevant academic research and scientific papers

Immobilization and continuous recycling of photoredox catalysts in ionic liquids for applications in batch reactions and flow systems: Catalytic alkene isomerization by using visible light

A catalytic (E)- to (Z)-isomerization of olefins using a photoredox catalyst under mild reaction conditions is presented. A variety of (Z)-alkenes can be prepared in the presence of visible light. A new reaction system allows an easy and efficient scale-up, as well as a continuous flow process in which the photocatalyst is immobilized in an ionic liquid and continuously recycled by simple phase separation. Catalytic (E)- to (Z)-isomerizations of olefins under mild conditions can be achieved by use of a photosensitizer and visible light. A new reaction system such as depicted allows an easy and efficient scale-up, as well as continuous flow processes in which the photocatalyst is immobilized in an ionic liquid and continuously recycled by phase separation.

Synthesis of stilbene analogues by one-pot oxidation-Wittig and oxidation-Wittig-Heck reaction

Synthesis of symmetrical (and unsymmetrical) stilbene derivatives is achieved by a combination of one-pot steps of Kornblum type oxidation of benzyl halide, its simultaneous in situ formation of phosphonium salt, and subsequently their Wittig reaction. In other variant it is oxidized to aldehyde, treated with ylide generated from phosphonium salt (CH3PPh3X) to give styrene, and subjected to Pd catalyzed Heck reaction with arylhalide to give stilbenes as the three-step one-pot sequence.

Unequivocal experimental evidence for a unified lithium salt-free wittig reaction mechanism for all phosphonium ylide types: Reactions with β-heteroatom-substituted aldehydes are consistently selective for cis-oxaphosphetane-derived products

The true course of the lithium salt-free Wittig reaction has long been a contentious issue in organic chemistry. Herein we report an experimental effect that is common to the Wittig reactions of all of the three major phosphonium ylide classes (non-stabilized, semi-stabilized, and stabilized): there is consistently increased selectivity for cis-oxaphosphetane and its derived products (Z-alkene and erythro-β-hydroxyphosphonium salt) in reactions involving aldehydes bearing heteroatom substituents in the β-position. The effect operates with both benzaldehydes and aliphatic aldehydes and is shown not to operate in the absence of the heteroatom substituent on the aldehyde. The discovery of an effect that is common to reactions of all ylide types strongly argues for the operation of a common mechanism in all Li salt-free Wittig reactions. In addition, the results are shown to be most easily explained by the [2+2] cycloaddition mechanism proposed by Vedejs and co-workers as supplemented by Aggarwal, Harvey, and co-workers, thus providing strong confirmatory evidence in support of that mechanism. Notably, a cooperative effect of ortho-substituents in the case of semi-stabilized ylides is confirmed and is accommodated by the cycloaddition mechanism. The effect is also shown to operate in reactions of triphenylphosphine-derived ylides and has previously been observed for reactions under aqueous conditions, thus for the first time providing evidence that kinetic control is in operation in both of these cases.

Copper-catalyzed highly selective semihydrogenation of non-polar carbon-carbon multiple bonds using a silane and an alcohol

A copper catalyst bearing a suitable Xantphos derivative or NHC ligand was found to be highly efficient for the selective semihydrogenation of non-polar unsaturated compounds using a mixture of a silane and an alcohol as reducing agent. The catalytic system was useful for the selective semihydrogenation of internal alkynes to (Z)-alkenes with suppression of overreduction to the corresponding alkanes. Furthermore, semihydrogenations of terminal alkyne, 1,2-diene, 1,3-diene, 1,3-enyne and 1,3-diyne systems were also achieved selectively. Copyright

Convenient and stereoselective synthesis of symmetrical (E)-stilbenes via homocoupling of 1,3-dibenzylbenzotriazolium bromides

Using NaH as the base and DMSO as the solvent, a series of symmetric (E)-stilbenes were prepared in good yields via the -homocoupling of 1,3-dibenzylbenzotriazolium bromides at room temperature. Georg Thieme Verlag Stuttgart · New York.

Ruthenium(II) porphyrin catalyzed cyclopropanation of alkenes with tosylhydrazones

The diastereoselective ruthenium(II) porphyrin catalyzed cyclopropanation of a variety of alkenes with aryl diazomethanes generated in situ from stable tosylhydrazone derivatives, was achieved in good to excellent yields (up to 92%) and product turnovers.

Co-operative ortho-effects on the Wittig reaction. Interpretation of stereoselectivity in the reaction of ortho-halo-substituted benzaldehydes and benzylidenetriphenylphosphoranes

The E/Z ratios of the stilbenes 1 formed in the Wittig reaction of ortho-halo substituted benzyltriphenylphosphonium salts 2 and benzaldehydes 3 were determined. It was found that there is a co-operative effect of one ortho-halo group on each of the two reacting partners which increases Z-selectivity, but two such groups on the same reactant gives high E-selectivity. The effects are strong enough to be preparatively significant in certain cases and can be interpreted within the modern framework of the Wittig mechanism established by Vedejs and co-workers.

Secondary Reactions of Sulfenes from Sulfonyl Chlorides and Tertiary Amines. 2. Formation of Episulfones, Sulfonylsulfene - Amine S,N-Adducts and Chlorsulfines from Primary Sulfonyl Chlorides and Tertiary Amines

The reaction of primary sulfonyl chlorides 1b-m with the tertiary amine bases quinuclidine, DABCO, Me3N, Et3N, Bu3N, EtiPr2N, and 1,2,2,6,6-pentamethylpiperidine is studied in acetonitrile solution between -40 and 80 deg C.The 2,3-dialkylthiirane 1,1-dioxides 4 (trans/cis > 1) and the alkenes 5 1> are obtained in high yields with Et3N at -40 deg C.The stereochemistry is influenced by the amine base B in the ring-closure reaction and partially by epimerization of the episulfones 4.Hindered bases favor the cis, β-branched sulfonyl chlorides the trans isomer.Competing formation of the sulfonylsulfene - amine S,N-adducts 7 is only observed with quinuclidine, DABCO, and Me3N, which are also the most active amines in the epimerization of the cis-2,3-diarylthiirane 1,1-dioxides 4.Methanesulfonyl chloride (1a) yields the mesylsulfene - amine S,N-adducts 7a with Me3N and Et3N in MeCN, but thiirane 1,1-dioxide (4a) with EtiPr2N in MeCN or with Et3N in Et2O.Formation of chlorosulfines 10 is favored by higher temperature (T > 20 deg C), hindered amine bases and β-branched sulfonyl chlorides.Isolation of 10g and 10h in high yields shows that tert-alkylchlorosulfines are rather stable sulfines.

ZEOLITE-CuNaY CATALYZED DECOMPOSITION OF ARYLDIAZOMETHANE

Decomposition of aryldiazomethanes is catalyzed by copper ion-exchanged Y-type zeolite to afford cis-1,2-diarylethylenes in high selectivity.The catalytic activity and selectivity are found to be affected by the exchange level of copper ions in zeolite and the solvent used.

sym-1,2-Diarylethylenes from α-Lithiated Benzylic Sulfones. Catalysis by Elemental Tellurium

The stability of α-lithiated alkyl, allyl, and benzyl phenyl sulfones was studied. α-Lithiated benzyl phenyl sulfones were found to give sym-1,2-diarylethylenes slowly when kept in tetrahydrofuran at ambient temperature for several days.The reaction time was significantly reduced if a catalytic amount (18-24percent) of elemental tellurium was present in the reaction.Other chalcogenides were less effective in this respect.The uncatalyzed reaction produced essentially pure trans olefins whereas the tellurium-catalyzed process afforded substantial amounts of cis isomer(usually 15-35percent).Tellurium tetrachloride in chloroform at ambient to reflux temperature was found to be highly effective in promoting cis/trans isomerization of 1,2-diarylethylenes.The involvement of a carbene mechanism or an intermolecular reaction of α-lithiated benzyl phenyl sulfones is considered in a mechanistic discussion.