128441-67-8

Upstream product

• 1165952-91-9 cyclohexa-1,3-diene 
• 107-02-8 acrolein 

Downstream Products

• 111036-01-2 2-(pyrrolidinomethylene)-bicyclo<2.2.2>octane 
• 19026-97-2 twistbrendane 

Relevant academic research and scientific papers

Titanium(IV) and zirconium(IV) sulfato complexes containing the Klaeui tripodal ligand: Molecular models of sulfated metal oxide surfaces

Treatment of titanyl sulfate in about 60 nM sulfuric acid with NaL, (L OEt = [(η5-C5H5)Co-{(P(O)(OEt) 2}3]-) afforded the μ-sulfato complex [(LOEtOEtTi)2(μ-O)2(μ-SO 4)] (2). In more concentrated sulfuric acid (> 1 M), the same reaction yielded the di-μ-sulfato complex [(LOEtTi) 2(μ-O)(μ-SO4)2] (3). Reaction of 2 with HOTf (OTf = triflate, CF3SO3) gave the tris-(triflato) complex [LOEtTi(OTf)3] (4), whereas treatment of 2 with Ag(OTf) in CH2Cl2 afforded the sulfato-capped trinuclear complex [{(LOEt)3Ti3(μ-O) 3}(μ3-SO4){Ag(OTf)}][OTf] (5), in which the Ag(OTf) moiety binds to a μ-oxo group in the Ti3(μ-O) 3 core. Reaction of 2 in H2O with Ba(NO3) 2 afforded the tetranuclear complex (LOEt) 4Ti4(μ-O)6 (6). Treatment of 2 with [{Rh(cod)Cl}2] (cod = 1,5-cyclooctadiene), [Re(CO)5Cl], and [Ru(tBu2-bpy)(PPh3)2Cl2] (tBu2bpy = 4,4′-dl-tert-butyl-2,2′-dipyridyl) in the presence of Ag(OTf) afforded the heterometallic complexes [(L OEt)2Ti2(O)2(SO4){Rh- (cod)}2][OTf]2 (7), [(LOEt)2Ti(O) 2-(SO4){Re(CO)3}][OTf] (8), and [{(L OEt)2Ti2(μ-O)}(μ3-SO 4)(μ-O)2{Ru-(PPh3)(tBu2bpy)}] [OTf]2 (9), respectively. Complex 9 is paramagnetic with a measured magnetic moment of about 2.4 μB. Treatment of zirconyl nitrate with NaLOEt in 3.5 M sulfuric acid afforded [(LOEt) 2Zr(NO3)][LOEtZr(SO4)-(NO 3)] (10). Reaction of ZrCl4 in 1.8 M sulfuric acid with NaLOEt in the presence Na2SO4 gave the μ-sulfato-bridged complex [LOEtZr(SO4)(H 2O)]2(μ-SO4) (11). Treatment of 11 with triflic acid afforded [(LOEt)2Zr][OTf]2 (12), whereas reaction of 11 with Ag(OTf) afforded a mixture of 12 and trinuclear [{LOEtZr(SO4)(H2O)}3(μ 3-SO4)][OTf] (13). The ZrIV triflato complex [LOEtZr-(OTf)3] (14) was prepared by reaction of L OEtZrF3 with Me3SiOTf. Complexes 4 and 14 can catalyze the Diels-Alder reaction of 1,3-cyclohexadiene with acrolein in good selectivity. Complexes 2-5, 9-11, and 13 have been characterized by X-ray crystallography.

Ring-opening-ring-closing metathesis of bicyclo[2.2.2]octenes: A novel synthesis of decalins and hydrindanes

Bicyclo[2.2.2]octenes containing an olefinic side-chain undergo ring-opening-ring-closing metathesis to give decalins and hydrindanes in reasonable yields.

A general approach to creating soluble catalytic polymers heterogenized in microcapsules

A general method for preparing site-isolated polymeric catalysts is presented. Linear chloromethyl and azide polymers have been sequestered within polyurea microcapsules and small molecule catalysts soaked through the shell walls to functionalize the soluble polymers. Reaction onto each type of support is quantitative and MacMillan, DMAP, and TEMPO test catalysts are shown to have faster reaction rates than the analogous resin-supported catalysts.

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.

Carbon's Three-Center, Four-Electron Tetrel Bond, Treated Experimentally

Tetrel bonding is the noncovalent interaction of group IV elements with electron donors. It is a weak, directional interaction that resembles hydrogen and halogen bonding yet remains barely explored. Herein, we present an experimental investigation of the

Synthetic studies toward polytwistane hydrocarbon nanorods

A synthetic strategy toward the intriguing hydrocarbon nanorod polytwistane is outlined. Our approach aims toward the polymerization of acetylene starting from precursors that would provide a helical bias for the formation of polytwistane. Both transition-metal-catalyzed and radical polymerizations were investigated. Two potential initiator molecules were synthesized that could be used for either approach. Although the intended regioselectivities were not observed, unusual organopalladium complexes and numerous compounds with novel carbon skeletons were obtained.

Carbocations as lewis acid catalysts in diels-alder and Michael addition reactions

In general, Lewis acid catalysts are metal-based compounds that owe their reactivity to a low-lying empty orbital. However, one potential Lewis acid that has received negligible attention as a catalyst is the carbocation. We have demonstrated the potential of the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels-Alder reaction for a range of substrates. Catalyst loadings as low as 500 ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the substituents on the tritylium ion, the Lewis acidity of the catalyst could be tuned to control the outcome of the reaction. The ability of this carbocation as a Lewis acid catalyst was also further extended to the Michael reaction. Copyright

Bromination and accompanying rearrangement of the polycyclic oxetane 2,4-oxytwistane

Bromination of the polycyclic oxetane 2,4-oxytwistane (rac-(1R,3S,4R,7S,9R,11S)-2-oxatetracyclo-[5.3.1.03,11.04,9]undecane) was undertaken in order to form 2,4-dibromotwistane. The oxetane was subjected to the mild reagent combinatio

Silylium ion-catalyzed challenging Diels-Alder reactions: The danger of hidden proton catalysis with strong Lewis acids

The pronounced Lewis acidity of tricoordinate silicon cations brings about unusual reactivity in Lewis acid catalysis. The downside of catalysis with strong Lewis acids is, though, that these do have the potential to mediate the formation of protons by various mechanisms, and the thus released Bronsted acid might even outcompete the Lewis acid as the true catalyst. That is an often ignored point. One way of eliminating a hidden proton-catalyzed pathway is to add a proton scavenger. The low-temperature Diels-Alder reactions catalyzed by our ferrocene-stabilized silicon cation are such a case where the possibility of proton catalysis must be meticulously examined. Addition of the common hindered base 2,6-di-tert-butylpyridine resulted, however, in slow decomposition along with formation of the corresponding pyridinium ion. Quantitative deprotonation of the silicon cation was observed with more basic (Mes)3P to yield the phosphonium ion. A deuterium-labeling experiment verified that the proton is abstracted from the ferrocene backbone. A reasonable mechanism of the proton formation is proposed on the basis of quantum-chemical calculations. This is, admittedly, a particular case but suggests that the use of proton scavengers must be carefully scrutinized, as proton formation might be provoked rather than prevented. Proton-catalyzed Diels-Alder reactions are not well-documented in the literature, and a representative survey employing TfOH is included here. The outcome of these catalyses is compared with our silylium ion-catalyzed Diels-Alder reactions, thereby clearly corroborating that hidden Bronsted acid catalysis is not operating with our Lewis acid. Several simple-looking but challenging Diels-Alder reactions with exceptionally rare dienophile/enophile combinations are reported. Another indication is obtained from the chemoselectivity of the catalyses. The silylium ion-catalyzed Diels-Alder reaction is general with regard to the oxidation level of the α,β-unsaturated dienophile (carbonyl and carboxyl), whereas proton catalysis is limited to carbonyl compounds.

Novel tetrahydroisoquinoline based organocatalysts for asymmetric Diels-Alder reactions: Insight into the catalytic mode using ROESY NMR and DFT studies

For the first time an organocatalyst bearing a secondary nitrogen within a cyclohexane ring has been evaluated in the asymmetric Diels-Alder reaction. This organocatalyst is also the first of its kind based on a (1R,3S)-6,7-dimethoxy- 1-phenyl-1,2,3,4-tetrahydroisoquinoline backbone. These catalysts were tested over a range of dienes and dienophiles and displayed promising chemical conversions of up to 100% with up to 64% ee with triflic acid as the cocatalyst. Density functional theory computational studies and 2D NMR spectroscopy were used to determine the structure of the intermediate iminium ion formed between the most efficient catalyst and cinnamaldehyde. The reaction profile for each of the four possibilities in this reaction were calculated and it was found that the iminium intermediate leading to the major product is higher in energy but kinetically preferred. The activation energies of all possible reaction paths were calculated and the results correlated with the observed products. These experiments revealed that the presence of both (E)- and (Z)-isomers of the cinnamaldehyde were contributing factors for the low enantioselectivity of the reaction products.