4457-59-4

Upstream product

• 34721-89-6 2-methyl-5-phenyl-furan 
• 96-47-9 2-methyltetrahydrofuran 
• 100-59-4 phenylmagnesium chloride 
• 102632-99-5 1-phenyl-4-penten-1-ol 
• 36866-66-7 5-phenyloxolan-2-ol 
• 917-54-4 methyllithium 
• 36842-33-8 2-iodomethyl-5-phenyltetrahydrofuran 
• 107-13-1 acrylonitrile 
• 624-49-7 dimethylfumarate 
• 89968-81-0 1-Phenylpentane-1,4-diol 
• 351422-26-9 C₁₄H₁₉NOS₂ 
• 182194-90-7 1-(1-Phenyl-pent-4-enyloxy)-1H-pyridine-2-thione 
• 16330-23-7 1-phenyl-1-pentyn-4-ol 
• 2344-71-0 5-phenylpentan-2-ol 

Relevant academic research and scientific papers

Nonclassical Mechanism in the Cyclodehydration of Diols Catalyzed by a Bifunctional Iridium Complex

1,4- and 1,5-diols undergo cyclodehydration upon treatment with cationic N-heterocyclic carbene (NHC)–IrIII complexes to give tetrahydrofurans and tetrahydropyrans, respectively. The mechanism was investigated, and a metal-hydride-driven pathway was proposed for all substrates, except for very electron-rich ones. This contrasts with the well-established classical pathways that involve nucleophilic substitution.

Visible-Light-Induced C-O Bond Formation for the Construction of Five- and Six-Membered Cyclic Ethers and Lactones

Visible-light-induced intramolecular C-O bond formation was developed using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT), which allows the regiocontrolled construction of cyclic ethers and lactones. The reaction is likely to proceed through the single-electron oxidation of the phenyl group, followed by the formation of a benzylic radical, thus preventing a competing 1,5-hydrogen abstraction pathway. Detailed mechanistic studies suggest that molecular oxygen is used to trap the radical intermediate to form benzyl alcohol, which undergoes cyclization. This new approach serves as a powerful platform by providing efficient access to valuable five- and six-membered cyclic ethers and lactones with a unified protocol.

Lewis Acid Mediated "endo-dig" Hydroalkoxylation-Reduction on Internal Alkynols for the Stereoselective Synthesis of Cyclic Ethers and 1,4-Oxazepanes

Lewis acid mediated 5/6/7-endo-dig hydroalkoxylation-reduction cascade on internal alkynols gave an expedient, stereoselective synthesis of cyclic ethers and 1,4-oxazepanes. The strategy has been extended to the first examples of hydroalkoxylation-alkyne

Nickel complex catalyzed efficient activation of sp3and sp 2c-h bonds for alkylation and arylation of oxygen containing heterocyclic molecules

A nickel(II) complex (1) of N,N'-bis(2,6-diisopropylphenyl)-2,6- pyridinedicarboxamido (L) ligand was examined for catalytic coupling of Grignard reagents with the C-H bond of oxygen containing heterocyclic compounds such as tetrahydrofuran and furan. The nickel( II) complex showed excellent activity in catalyzing C-H activation and further coupling with various Grignard reagents. The effective activation of the C-H bond proceeded under ambient reaction conditions with a short reaction time (1-2 h). The catalyst (1) displays high turnover frequency of 4,130 h-1with catalyst loading as low as 0.01 mol%. This catalytic route could prove to be an efficient mode of activation of sp3and sp2C-H bonds in various heterocycles for the preparation of synthetically and pharmaceutically relevant molecules. Springer Science+Business Media New York 2013.

An aerobic oxidation/homolytic substitution-cascade for stereoselective methylsulfanyl-cyclization of 4-pentenols

4-Pentenols (dihomoallylic alcohols) are oxidized by cobalt(ii)-activated dioxygen in solutions of dimethyl disulfide and cyclohexa-1,4-diene to afford methylsulfanyl (CH3S)-functionalized tetrahydrofurans in up to 74% yield. The reaction is a cascade, composed of oxidative alkenol cyclization providing tetrahydrofuryl-2-methyl radicals, which are trapped in dimethyl disulfide. Homolytic methylsulfanyl substitution by carbon radicals is a slow reaction, as exemplified by the rate constant of kSCH3 = 3 × 104 M-1 s-1 (70 °C) derived from competition kinetics for the reaction between dimethyl disulfide and the trans-2-phenyltetrahydrofuryl-5-methyl radical. Methylsulfanyl-cyclizations therefore are experimentally performed in neat dimethyl disulfide, containing the minimum amount of cyclohexa-1,4-diene necessary for attaining almost quantitative alkenol conversion. The oxidative tetrahydrofuran synthesis occurs with noteworthy (>99%) 2,5-trans-stereoselectivity, as shown by the synthesis of diastereomerically pure 2,3- and 2,3,3-substituted 5-(methylsulfanyl) methyltetrahydrofurans from stereodefined 1,2-di- and 1,2,2-trisubstituted 4-pentenols. Changing the chemical nature of the disulfide reagent or the alkenol extends the scope of alkylsulfanyl-cyclization to ethylsulfanyl- cyclization, allylsulfanyl-transfer, or tetrahydropyran synthesis.

New method for C-H arylation/alkylation at α-position of cyclic aliphatic ethers by iron-oxide mediated reaction

We report a new and efficient iron oxide catalyzed cross-coupling reaction between organometallic species such as alkyl/arylmagnesium halides or organolithium species and α-hydrogen bearing cyclic unbranched and branched aliphatic ethers via activation of C(sp3)-H. In the presence of 1 mol% of iron oxide, five and six membered unbranched cyclic ethers such as tetrahydrofuran and tetrahydropyran gave good to excellent yields of cross-coupled products. Whereas, in case of branched ether such as 2-methyltetrahydrofuran, it was observed that the arylation occurred at both the sides and gave moderate yields of a mixture of regioisomers. Among the organometallic species used, alkyl organometallic reagents gave less yields as compared to aryl organometallics.

Functionalized tetrahydrofurans from alkenols and olefins/alkynes via aerobic oxidation-radical addition cascades

Aerobic oxidation of alkyl- and phenyl-substituted 4-pentenols (bishomoallyl alcohols), catalyzed by cobalt(II) complexes in solutions of γ-terpinene or cyclohexa-1,4-diene, stereoselectively gave tetrahydrofurylmethyl radicals. Cyclized radicals were tra

Efficient intramolecular hydroalkoxylation of unactivated alkenols mediated by recyclable lanthanide lriflate ionic liquids: Scope and mechanism

Lanthanide triflate complexes of the type [Ln(OTf)3] (Ln = La, Sm, Nd, Yb, Lu) serve as effective, recyclable catalysts for the rapid intramolecular hydroalkoxylation (HO)/cyclization of primary/secondary and aliphatic/aromatic hydroxyalkenes in imidazolium-based room-temperature ionic liquids (RTILs) to yield the corresponding furan, pyran, spirobicyclic furan, spirobicyclic furan/pyran, benzofuran, and isochroman derivatives. Products are straightforwardly isolated from the catalytic solution, conversions exhibit Markovnikov regioselectivity, and turnover frequencies are as high as 47 h -1 at 120°C. The ring-size rate dependence of the primary alkenol cyclizations is 5>6, consistent with a sterically controlled transition state. The hydroalkoxylation/cyclization rates of terminal alkenols are slightly more rapid than those of internal alkenols, which suggests modest steric demands in the cyclic transition state. Cyclization rates of aryl-functionalized hydroxyalkenes are more rapid than those of the linear alkenols, whereas five- and five/six-membered spirobicyclic skeletons are also regioselectively closed. In cyclization of primary, sterically encumbered alkenols, turnoverfrequency dependence on metal-ionic radius decreases by approximately 80fold on going from La3+ (1.160 A) to Lu3+ (0.977 A), presumably reflecting steric impediments along the reaction coordinate. The overall rate law for alkenol hydroalkoxylation/cyclization is v≈[catalys] 1[alkenol]1. An observed ROH/ROD kinetic isotope effect of 2.48 (9) is suggestive of a catalytic pathway that involves kinetically significant intramolecular proton transfer. The present activation parameters-enthalpy (ΔH≠) = 18.2 (9) Kcal mol-1, entropy (ΔS≠) = -17.0 (1.4) eu, and energy (E,) = 18.2 (8) kcal mol-1-suggest a highly organized transition state. Proton scavenging and coordinative probing results suggest that the lanthanide inflates are not simply precursors of free triflic acid. Based on the kinetic and mechanistic evidence, the proposed catalytic pathway invokes hydroxyl and olefin activation by the electron-deficient Ln3+ center, and intramolecular H+ transfer, followed by alkoxide nucleophilic attack with ring closure.

Reductive and brominative termination of alkenol cyclization in aerobic cobalt-catalyzed reactions

(Chemical Equation Presented) Tetrahydrofur-2-ylmethyl radicals were stereoselectively generated from substituted pent-4-en-1-ols in aerobic cobalt(II)-catalyzed oxidations. Intermediates were trapped with cyclohexa -1,4-diene, γ-terpinene, BrCCl3, diethyl dibromomalonate, or electron-deficient olefins such as acrylonitrile or dimethyl fumarate to afford functionalized tetrahydrofurans in synthetically useful yields.

Activation of molecular oxygen and its use in stereoselective tetrahydrofuran-syntheses from δ,ε-unsaturated alcohols

Bishomoallylic alcohols (pent-4-en-1-ols) underwent efficient oxidative cyclizations, if treated with O2 and bis{2,2,2-trifluoromethyl-1- [(1R,4S)-1,7,7-trimethyl-2-(oxo-κO)bicyclo[2.2.1]hept-3-yliden] ethanolato-κO}cobalt(ii) in solutions of 2-propanol at 60 °C. Ring closures occurred diastereoselectively and afforded 2,3-trans- (96% de), 2,4-cis- (～60% de), and 2,5-trans-substituted (>99% de) (phenyl)tetrahydrofur-2-ylmethanols as major components. Formation of bicyclic compounds and a 2,3,4,5-substituted oxolane was feasible as exemplified by syntheses of oxabicyclo[4.3.0]nonylmethanols and a derivative of natural product magnosalicin in 61-72% (90-99% de). The effectiveness of tetrahydrofuran synthesis was critically dependent on (i) solvent, (ii) reaction temperature, (iii) initial cobalt concentration, (iv) chain length between hydroxyl and vinyl groups, and (v) substitution at reacting entities. A sequence is proposed for rationalizing observed selectivities.