20758-63-8

Upstream product

• 20758-61-6 cyclopentyl(4-methoxyphenyl)methanol 
• 1398415-49-0 1-(6-iodohex-1-yn-1-yl)-4-methoxybenzene 
• 2564-83-2 2,2,6,6-tetramethyl-piperidine-N-oxyl 
• 7333-52-0 cyclopenthyltriphenylphosphonium bromide 
• 123-11-5 4-methoxy-benzaldehyde 
• 21482-00-8 Cyclopentylidene-triphenyl-λ⁵-phosphane 
• 104-92-7 1-bromo-4-methoxy-benzene 
• 36601-82-8 N′-(cyclopentylmethylene)-4-methylbenzenesulfonohydrazide 
• 872-53-7 cyclopentanealdehyde 
• 126613-16-9 1-(benzenesulfonyl)-2-(p-methoxyphenyl)acetylene 
• 1608-24-8 3-(2,2-difluoroethenyl)anisole 
• 23708-47-6 1,4-bis(bromomagnesium)butane 
• 768-60-5 4-methoxyphenylacetylen 
• 4250-54-8 2-(1-naphthyl)-1,3-dioxa-2-borol 

Relevant academic research and scientific papers

Silver-Catalysed Hydroarylation of Highly Substituted Styrenes

Hydroarylation is an effective strategy to rapidly increase the complexity of organic structures by transforming flat alkene moieties into three-dimensional frameworks. Many strategies have already been developed to achieve the hydroarylation of styrenes,

Synthesis of α-Arylated Cycloalkanones from Congested Trisubstituted Spiro-epoxides: Application of the House-Meinwald Rearrangement for Ring Expansion

A three-step sequence for the synthesis of α-arylated cyclohexanones and the most challenging cycloheptanones is reported. First, an efficient one-pot synthesis of β,β'-disubstituted benzylidene cycloalkanes (styrenes) using the palladium-catalyzed Barluenga reaction from readily available feedstock chemicals is described. Furthermore, an epoxidation followed by the House-Meinwald rearrangement (HMR) of spiro-epoxides is reported to produce a number of α-arylated cycloalkanones upon ring expansion. Reactions catalyzed by bismuth triflate underwent quasi-exclusively ring expansion for all substrates (electronically poor and rich), with yields ranging from 15% to 95%, thus demonstrating the difficulty of achieving ring enlargement for electron-deficient spiro-epoxides. On the other hand, by means of catalysis with aluminum trichloride, the rearrangement of spiro-epoxides proceeded typically in high yields and with remarkable regioselectivity on a broader substrate scope. In this case, a switch of regioselectivity was achieved for spiro-epoxides with electron-withdrawing substituents which enable the method to be successfully extended to some chemospecific arene shifts and the synthesis of aldehydes bearing a α-quaternary carbon. While the HMR has been extensively studied for smaller ring enlargement, we are pleased to report herein that larger cyclohexanones and cycloheptanones can be obtained efficiently from more sterically demanding trisubstituted spiro-epoxides bearing electron-releasing and electron-neutral arene substituents.

Switchable Synthetic Strategy toward Trisubstituted and Tetrasubstituted Exocyclic Alkenes

An efficient and facile method for the construction of tri- or tetrasubstituted exocyclic alkenes is achieved via a Cu(I)-catalytic system. This protocol exhibits mild conditions, low-cost catalyst, good functional group tolerance, and good yields. The selectivity toward tri- or tetrasubstituted alkenes can be delicately controlled by adjustment of base and solvent. A preliminary mechanism study manifested that the reaction undergoes a radical process, where B2pin2 plays an indispensable role.

Consecutive visible-light photoredox decarboxylative couplings of adipic acid active esters with alkynyl sulfones leading to cyclic compounds

Novel and efficient consecutive photoredox decarboxylative couplings of adipic acid active esters (bis(1,3-dioxoisoindolin-2-yl)-substituted hexanedioates) with substituted 1-(2-arylethynylsulfonyl)benzenes have been developed under visible-light photocatalysis. The successive photoredox decarboxylative C-C bond formation at room temperature afforded the corresponding cyclic compounds in good yields with tolerance of some functional groups.

Synthesis of Exocyclic Trisubstituted Alkenes via Nickel- Catalyzed Kumada-Type Cross-Coupling Reaction of gem- Difluoroalkenes with Di-Grignard Reagents

A practical, nickel-catalyzed Kumada-type double cross-coupling reaction of gem-difluoroalkenes with 1,4- or 1,5-di-Grignard reagents was developed. The reaction proceeded efficiently at room temperature and a variety of cyclization products, arylmethylenecyclopentanes and arylmethylenecyclohexanes, were obtained in high to excellent yields, respectively.

Aryltriolborates as air- and water-stable bases for wittig olefination

Tetrabutylammonium aryltriolborates have been synthesized in 37-66% yield by a one-pot procedure from arylboronic acids, 1,1,1-tris(hydroxymethyl)ethane, and aqueous tetrabutylammonium hydroxide. The aryltriolborates can be used as bases in Wittig reactions of aromatic aldehydes with all three types of phosphorus ylides: stabilized and semistabilized ylides can be generated at room temperature, and nonstabilized ylides at 120 °C (bath temperature).

Palladium-catalyzed alkyne insertion/reduction route to trisubstituted olefins

A new route to trisubstituted olefins through a palladium-catalyzed alkyne insertion/reduction reaction with unactivated alkyl iodides is reported. The reaction proceeds under mild conditions and tolerates a range of functional groups and substitution patterns. Preliminary mechanistic inquiry suggests that the transformation may proceed through a hybrid radical/organometallic pathway.

Palladium-catalyzed alkyne insertion/Suzuki reaction of alkyl iodides

A palladium-catalyzed alkyne insertion/Suzuki reaction with unactivated alkyl iodides is described. Under the reaction conditions, selective migratory insertion of alkynes avoids β-hydride elimination and provides a facile synthesis of stereodefined, tetrasubstituted olefins. The transformation offers broad substrate scope for both the alkyl iodide and boron nucleophile. Mechanistic studies have revealed inversion of the stereocenter for the carbon bearing the iodide.

Cyclizations during the Grignard Reactions of ω-Bromoalkynes

The Grignard reactions of a number of ω-bromoalkynes have been shown to undergo regioselective cyclizations in certain instances to give the smaller possible carbocycle. These cyclizations are shown to result from two competing processes, whose relative efficiencies depend upon the chain length and the remote substitutent on the acetylene. These are interpreted as a radical cyclization which occurs only during the time the Grignard is being formed from the bromide and an organometallic reaction which slowly transforms the Grignard reagent into its cyclic isomer. The mechanistic details of these transformations are discussed.

Cyclizations of ω-Alkynyl Halides by Cr(II) Reduction

Reduction of halides of the types RCC(CH2)nX with Cr(II) in aqueous DMF containing ethylenediamine proceeds by way of the intermediate radicals which cyclize regioselectively in the n=4 and n=5 cases to give substituted methylenecycloalkanes.Experimental conditions which favor longer lifetimes for the intermediate radicals (low concentrations, slow addition times, and an inverse-addition mode) result in increased cyclization.The iodides curiously give more cyclic product than the corresponding bromides.These results are discussed.