18684-79-2

Usage

Synthesis Reference(s)

Tetrahedron Letters, 26, p. 1651, 1985 DOI: 10.1016/S0040-4039(00)98575-7

Upstream product

• 943-89-5 (E)-3-(4-methoxyphenyl)acrylic acid 
• 830-09-1 3-(4'-methoxyphenyl)propenoic acid 
• 156-59-2 cis-1,2-Dichloroethylene 
• 25679-28-1 cis-Anethole 
• 880634-12-8 5-[(chloromethyl)sulfonyl]-1-phenyl-1H-tetrazole 
• 123-11-5 4-methoxy-benzaldehyde 
• 5676-64-2 (Z)-3-(4-methoxyphenyl)acrylic acid 
• 103721-97-7 (4R,5R)-4-Chloro-5-(4-methoxy-phenyl)-[1,3]oxathiolane 3,3-dioxide 
• 91309-65-8 3-chloro-3-(p-methoxybenzyl)diazirine 
• 76151-58-1 2-<(chloromethyl)sulfonyl>benzothiazole 
• 3167-62-2 diethyl (dichloromethyl)phosphonate 
• 691-38-3 (Z)-4-methyl-2-pentene 
• 637-69-4 4-Methoxystyrene 

Relevant academic research and scientific papers

HALOGEN-CONTAINING METATHESIS CATALYSTS AND METHODS THEREOF

The present disclosure provides compounds, compositions, and methods for preparing alkenyl halides and/or haloalkyl-substituted olefins with Z-selectivity. The methods are particularly useful for preparing alkenyl fluorides such as CF3-substituted olefins by means of cross-metathesis reactions using halogen-containing molybdenum and tungsten complexes.

Molybdenum chloride catalysts for Z-selective olefin metathesis reactions

The development of catalyst-controlled stereoselective olefin metathesis processes has been a pivotal recent advance in chemistry. The incorporation of appropriate ligands within complexes based on molybdenum, tungsten and ruthenium has led to reactivity and selectivity levels that were previously inaccessible. Here we show that molybdenum monoaryloxide chloride complexes furnish higher-energy (Z) isomers of trifluoromethyl-substituted alkenes through cross-metathesis reactions with the commercially available, inexpensive and typically inert Z-1,1,1,4,4,4-hexafluoro-2-butene. Furthermore, otherwise inefficient and non-stereoselective transformations with Z-1,2-dichloroethene and 1,2-dibromoethene can be effected with substantially improved efficiency and Z selectivity. The use of such molybdenum monoaryloxide chloride complexes enables the synthesis of representative biologically active molecules and trifluoromethyl analogues of medicinally relevant compounds. The origins of the activity and selectivity levels observed, which contradict previously proposed principles, are elucidated with the aid of density functional theory calculations.

Solid-phase oxidative halodecarboxylation of β-arylacrylic acids with the ceric ammonium nitrate-alkali halide system

The solid-phase oxidation of cinnamic, 4-methoxy- and 3,4-dimethoxycinnamic acids with Ce(NH4)2(NO3)6-MHal system leads to β-halostyrenes. Similar procedure in the absence of a metal halide results in a cleavage of the C=C bond giving the corresponding benzaldehydes.

Stereoselective synthesis of Z alkenyl halides via Julia olefination

Julia olefination between α-halomethyl sulfones and a variety of aldehydes afforded alkenyl halides in good to excellent yields with high E/Z stereoselectivities. Sulfones were readily prepared in two or three steps from commercially available reagents in good yields. Optimization revealed that the nature of the solvent, the base, and the additive were crucial to obtain the desired alkenyl halides.

Microwave induced halodecarboxylation of α,β-unsaturated carboxylic acids

Halodecarboxylations of α,β-unsaturated carboxylic acids 1a-g, 4 by N-cholorobenzotriazole under 5-10 minutes of microwave irradiation gave the corresponding β-arylvinyl halides 3a-g, 5 in yields of 70-90%.

Stereoselective synthesis of (E)-β-arylvinyl halides by microwave-induced Hunsdiecker reaction

(E)-β-Arylvinyl halides were prepared in high yields in a short reaction (1-2 min) by microwave irradiation of the corresponding 3-arylpropenoic acids in the presence of N-halosuccinimide and catalytic LiOAc.

Oxidative Halo-Decarboxylation of α,β-Unsaturated Carboxylic Acids

A procedure for oxidative halo-decarboxylation of α,β-unsaturated carboxylic acids using iodosylbenzene, or iodosylbenzene diacetate, and N-chloro-, N-bromo-, or N-iodosuccinimide is presented.Good yields of the corresponding bromoalkenes are obtained when the α,β-unsaturated carboxylic acids are substituted with an aromatic substituent in the β-position and N-bromosuccinimide is used as the halogenation reagent.The scope of mainly the oxidative bromo-decarboxylation reaction is presented, and a tentative mechanism is proposed.

Stereochemistry of direct olefin formation from carbonyl compounds and lithiated heterocyclic sulfones

The conditions for the title reaction were studied for the 2-benzothiazole and 2-pyridine series and for some examples in the 2-pyrimidine series.The olefin preparations were generally observed to be more efficient for 2-BT-sulfone systems.From the data of the hundred cases studied, it can be concluded that (E)-olefins are obtained: (i) from saturated BT-sulfones and aromatic aldehydes; and (ii) from benzylic BT-sulfones and branched saturated aldehydes (isobutyraldehyde, pivalaldehyde) or α,β-ethylenic or aromatic aldehydes. (Z)-olefins arise: (i) fom propargylic BT-sulfones and saturated or aromatic aldehydes; and (ii) from allylic or benzylic Pyr-sulfones and saturated aldehydes.Possible mechanisms for this new olefination procedure were examined. - heteroaromatic sulfones, organolithium derivatives, intramolecular ipso reactions, stereochemistry, elimination, olefination.

Highly cis-selective Wittig reactions employing α-heterosubstituted ylids

1-Alkenyl chlorides, bromides or iodides can be obtained with very high cis selectivities through Wittig reaction employing α-chloro, α-bromo α-iodo ylids derive from tris(2-methoxymethoxyphenyl)phospine. The corresponding α-methoxy substituted ylid produces enethers with again remarkably high cis/trans ratios. Palladium(II) catalyzed coupling of (Z)-1-iodo-1-heptene with ethyl acrylate affords ethyl (2E,4Z)-2-4-decadienoate, the Bartlett pear fragrance, with almost quantitative yield.

Carbanions phosphonate prepares par voie electrochimique: formation et reactivite vis-a-vis d'un aldehyde

Reactivity towards p-methoxybenzaldehyde (ArCHO) of electrochemically generated phosphonate carbanions has been investigated.Electrolyses were carried out at a mercury cathode in DMF and two routes to the desired carbanion have been compared: (i) Deprotonation of phosphonates of general formula (EtO)2P(O)CHYW (Y = W = Cl; Y = H, W = Cl; Y = Cl, W = CO2Et; Y = H, W = CO2Et; Y = CH3, W = CO2Et; Y = Cl, W = CH3), by the bases resulting from the electroreduction of azobenzene; addition of the carbanion formed onto the carbonyl group takes place and leads to the adduct (EtO)2P(O)CYW(Ar)O-. (ii) Two-electron reduction of halophosphonates (EtO)2P(O)CXYW (X = Cl, Y and W as above; X = Br, W = CO2Et, Y = Cl, Br, or CH3); when no H atom is present on the carbon bearing the phosphonate group (Y and W no = H), the same evolution leading to the above adduct is observed, on the contrary, when Y = H, the electrogenerated carbanion deprotonates the substrate and the resulting carbanion (EtO)2P(O)CXW reacts with the aldehyde; giving the adduct (EtO)2P(O)CXW(Ar)O-.Evolution of the intermediate adduct depends on the substituents Y (or X) and W: when W = CO2Et, whatever the nature of Y (or X), diethyl phosphate is eliminated with formation of the ethylenic ArCH=CWY (or X) (Wittig-Horner reaction); the same evolution is observed when Y = W = Cl.When W = Cl and Y = H or CH3, the final product is the phosphonate epoxyde resulting from chloride elimination (Darzens reaction).Chemo- and stereoselectivity depend only on the nature of Y and W but are independent of the mode of generation of the carbanion.Yields are limited by side-protonation reactions, which are related to the basicity of the phosphonate carbanions.Analysis of the results permits selection of the optimal electrolysis conditions for purposes of synthesis.Key words: electrosynthesis, electrogenerated bases, phosphonates, Wittig-Horner.