933-44-8

Upstream product

• 78-85-3 2-methylpropenal 
• 78-79-5 isoprene 
• 123-73-9 crotonaldehyde 
• 16695-87-7 1,4-dimethylcyclohex-3-ene-1-carboxylic acid 
• 50552-16-4 1,4-Dimethyl-4-nitrosooxymethyl-cyclohexene 
• 50552-12-0 1,4-Dimethyl-3-cyclohexen-1-methanol 

Downstream Products

• 919170-38-0 2,2,2-trichloro-1-(1,4-dimethylcyclohex-3-enyl)ethanol 
• 919171-55-4 2,2-dibromo-1-(1,4-dimethylcyclohex-3-enyl)ethanol 

Relevant academic research and scientific papers

Iodine-Catalyzed Diels-Alder Reactions

The Diels-Alder cycloaddition is the most popular pericyclic reaction with numerous applications in synthesis and catalysis. We now demonstrate that we can perform this reaction under mild and metal-free conditions relying on molecular iodine as the catalyst. Cycloadditions with cyclohexadiene, cyclopentadiene, or isoprene with various dienophiles can be performed typically within minutes in moderate to good yields and high endo selectivity. The mechanistic studies including kinetic and DFT investigations clearly indicate a halogen-bond activation and rule out other modes of activation. Furthermore, iodine performs equally well as typical metallic Lewis acids like AlCl3, SnCl4, or TiCl4.

Diazepane Carboxylates as Organocatalysts in the Diels–Alder Reaction of α-Substituted Enals

Ethyl diazepane carboxylate efficiently catalyzes the Diels–Alder cycloaddition of α-substituted-α,β-unsaturated aldehydes via iminium ion organocatalysis. The reaction is applicable to a range of dienes and dienophiles and generally proceeds at room temperature in the presence of 5 mol-% catalyst and 2.5 mol-% triflic acid co-catalyst. The incorporation of a stereogenic center on the diazepane backbone in combination with a menthyl carbamate produces a catalyst which affords enantioselectivities of 70–95 % ee for the cycloaddition of cyclopentadiene with a range of dienophiles. The enantioselectivity is rationalized via a transition state in which electrostatic stabilization by the carboxylate directs the diene to the more hindered face of the dienophile.

Lewis Acids as Activators in CBS-Catalysed Diels–Alder Reactions: Distortion Induced Lewis Acidity Enhancement of SnCl4

The effect of several Lewis acids on the CBS catalyst (named after Corey, Bakshi and Shibata) was investigated in this study. While2H NMR spectroscopic measurements served as gauge for the activation capability of the Lewis acids, in situ FT-IR spectroscopy was employed to assess the catalytic activity of the Lewis acid oxazaborolidine complexes. A correlation was found between the Δδ(2H) values and rate constants kDA, which indicates a direct translation of Lewis acidity into reactivity of the Lewis acid–CBS complexes. Unexpectedly, a significant deviation was found for SnCl4as Lewis acid. The SnCl4–CBS adduct was much more reactive than the Δδ(2H) values predicted and gave similar reaction rates to those observed for the prominent AlBr3–CBS adduct. To rationalize these results, quantum mechanical calculations were performed. The frontier molecular orbital approach was applied and a good correlation between the LUMO energies of the Lewis acid–CBS–naphthoquinone adducts and kDAcould be found. For the SnCl4–CBS–naphthoquinone adduct an unusual distortion was observed leading to an enhanced Lewis acidity. Energy decomposition analysis with natural orbitals for chemical valence (EDA-NOCV) calculations revealed the relevant interactions and activation mode of SnCl4as Lewis acid in Diels–Alder reactions.

Enantioselective catalysts based on the chiral fragment (η5-C5Me5)Ir(Prophos) for Diels-Alder reactions

The aqua complex (SIr,RC)-[(η5-C 5Me5)Ir(Prophos)(H2O)][SbF6] 2 [Prophos = (R)-propane-1,2-diyl-bis(diphenylphosphane)] is an active precursor for the asymmetric Diels-Alder reaction of acyclic enals with cyclopentadiene, 2,3-dimethylbutadiene and isoprene. Enantioselectivities up to 78% ee are achieved. The intermediate Lewis acid-dienophile complex (S Ir,RC)-[(η5-C5Me 5)Ir(Prophos)(ethyl acrolein)][SbF6]2 has been isolated and completely characterized, including the X-ray crystal structure determination. Structural parameters indicate that the disposition of the coordinated dienophile is controlled by CH/π attractive interactions established between a phenyl group of the Prophos ligand and the aldehyde proton of the coordinated enal. Proton NMR data indicate that these interactions are maintained in solution. From diffractometric and spectroscopic data, the origin of the enantioselectivity is discussed.

Synthesis, characterization, and catalytic properties of new electrophilic iridium(III) complexes containing the (R)-(+)-2,2,′-binaphthyl Ligand

The oxidative addition of MeI to the Ir(I) square-planar complex IrI(CO)((R)-(+)-BINAP) where (R)-(+)-BINAP = (R)-(+)-2,2′- bis(diphenylphosphino)-1,′-binaphthyl)) results in the formation of two diastereomers in a 2:1 ratio of the Ir(III) oxidative addit

Unsaturated aldehydes as alkene equivalents in the Diels-Alder reaction

A one-pot procedure is described for using α,β-unsaturated aldehydes as olefin equivalents in the Diels-Alder reaction. The method combines the normal electron demand cycloaddition with aldehyde dienophiles and the rhodium-catalyzed decarbonylation of aldehydes to afford cyclohexenes with no electron-with-drawing substituents. In this way, the aldehyde group serves as a traceless control element to direct the cycloaddition reaction. The Diels-Alder reactions are performed in a diglyme solution in the presence of a catalytic amount of boron trifluoride etherate. Subsequent quenching of the Lewis acid, addition of 0.3% of [Rh(dppp)2Cl] and heating to reflux achieves the ensuing decarbonylation to afford the product cyclohexenes. Under these conditions, acrolein, crotonaldehyde and cinnamaldehyde have been reacted with a variety of 1,3-dienes to afford cyclohexenes in overall yields between 53 and 88%. In these transformations, the three aldehydes serve as equivalents of ethylene, propylene and styrene, respectively.

[AlCl3 + 2THF]: A new and efficient catalytic system for Diels-Alder cycloaddition of α,β-unsaturated carbonyl compounds under solvent-free conditions

[AlCl3 + 2THF] is a new catalytic system for the Diels-Alder cycloaddition under SFC and air atmosphere. By using equimolar amounts of reactants, this catalyst prevents the polymerization of the diene and allows the corresponding adducts to be isolated with high regio- and stereocontrol and in excellent yields.

Synthesis and Claisen rearrangement of bridged bicyclic enol ethers of relevance to the course of ketene s-cis-diene cycloaddition

The synthesis is described of a range of 3-alkylidene-2-oxabicyclo[2.2.1] hept-5-ene and 3-alkylidene-2-oxabicyclo[2.2.2]oct-5-ene derivatives; Claisen rearrangement of these substrates either thermally or in the presence of an added Lewis acid results in

Oxazaborolidine-derived Lewis acid assisted Lewis acid as a moisture-tolerant catalyst for enantioselective Diels-Alder reactions

Reactive, selective, and tough, the chiral Lewis acid generated from 1 and SnCl4 catalyzes the enantioselective Diels-Alder reactions of various classes of substrates (see scheme). The reactive species preserves its asymmetric induction ability even in the presence of a large excess of SnCl 4. Importantly, this catalyst system is tolerant to a small amount of moisture, oxygen, and Lewis bases.

Ionic liquids and their use

Ionic compounds having a freezing point of no more than 50° C., formed by the reaction of at least one amine salt of the formula R1R2R3R4N+X? (I) with at least one hydrated salt, which is a chloride, nitrate, sulphate or acetate of Li, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, Bi, La or Ce; wherein R1, R2 and R3 are each independently a C1 to C5 alkyl or a C6 to C10 cycloalkyl group, or wherein R2 and R3 taken together represent a C4 to C10 alkylene group, thereby forming with the N atom of formula (I) a 5 to 11 membered heterocyclic ring, and wherein R4 is hydrogen, or phenyl, or C1 to C12 alkyl or cycloalkyl group, optionally substituted with at least one group selected from OH, Cl, Br, F, I, phenyl, NH2, CN, NO2, COOR5, CHO, COR5 and OR5, wherein R5 is a C1 to C10 alkyl or cycloalkyl group, and X? is an anion capable of being complexed by the said hydrated salt. The compounds are useful as solvents, electrolytes, and catalysts, and have particular application in solvents/electrolytes for metal plating and electropolishing processes, in particular in chromium plating.