197155-67-2

Upstream product

• 3377-20-6 diethyl methylenemalonate 
• 513-81-5 2,3-dimethyl-buta-1,3-diene 
• 406498-43-9 diethyl but-3-yn-1-yl(prop-2-en-1-yl)propanedioate 
• 609-08-5 Diethyl methylmalonate 
• 105-53-3 diethyl malonate 
• 2049-80-1 (2-propenyl)propanedioic acid diethyl ester 
• 1575-67-3 2-(2-methyl-allyl)-malonic acid diethyl ester 

Downstream Products

• 74235-35-1 3.4-Dimethyl-3-cyclohexen-1.1-dimethanol 

Relevant academic research and scientific papers

Recent advances in olefin metathesis and its application in organic synthesis

Recent advances in olefin metathesis, focusing on the areas of ring- closing olefin metathesis (RCM) and cross metathesis, are reviewed. Among numerous complexes which show catalytic activities in olefin metathesis, recently developed well-defined [Mo] an

Copper-Catalyzed Dehydrogenative Diels-Alder Reaction

A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.

IMIDAZOLIDINE-BASED METAL CARBENE METATHESIS CATALYSTS

The present invention relates to novel metathesis catalysts with an imidazolidine-based ligand and to methods for making and using the same. The inventive catalysts are of the formula wherein: M is ruthenium or osmium;X and X1 are each independently an anionic ligand;L is a neutral electron donor ligand; and,R, R1, R6, R7, R8, and R9 are each independently hydrogen or a substituent selected from the group consisting of C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthiol, aryl thiol, C1-C20 alkylsulfonyl and C2-C20 alkylsulfinyl, the substituent optionally substituted with one or more moieties selected from the group consisting of C1-C10 alkyl, C1-C10 alkoxy, aryl, and a functional group selected from the group consisting of hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen. The inclusion of an imidazolidine ligand to the previously described ruthenium or osmium catalysts has been found to dramatically improve the properties of these complexes. The inventive catalysts maintains the functional group tolerance of previously described ruthenium complexes while having enhanced metathesis activity that compares favorably to prior art tungsten and molybdenum systems.

Rendering schrock-type molybdenum alkylidene complexes air stable: User-friendly precatalysts for alkene metathesis

A matter of convenience: Schrock molybdenum alkylidenes are amongst the most powerful olefin metathesis catalysts known to date, but their sensitivity to air and moisture mandates their handling in a glove-box or by Schlenk techniques. This inconvenience is circumvented by using the corresponding phenanthroline- or bipyridine adducts, which are bench-stable and hence very user-friendly. The active species can be liberated from these precatalysts in uncompromised form on treatment with ZnCl2 in toluene (see scheme).

Desymmetrizations forming tetrasubstituted olefins using enantioselective olefin metathesis

Figure presented Highly reactive chiral Ru-based catalysts possessing C1-symmetric N-heterocyclic carbene ligands adorned with one N-alkyl group and one N-aryl group were evaluated in asymmetric desymmetrizations to form cyclic products possess

[(NHC)(NHCewg)RuCl2(CHPh)] complexes with modified NHCewg ligands for efficient ring-closing metathesis leading to tetrasubstituted olefins

Imidazolium salts (NHCewg-HCl) with electronically variable substituents in the 4,5-position (H,H or C1,C1 or H,NO2 or CN 5CN) and sterically variable substituents in the 1,3-position (Me,Me or Et,Et or iPr,iPr or Me,iPr) were synthesized and converted into the respective [AgI(NHC)ewg] complexes. The reactions of [(NHC)RuCl 2(CHPh)(Py)2] with the [AgI(NHQw8)] complexes provide the respective [(NHC)(NHCewg)RuCl2(CHPh)] complexes in excellent yields. The catalytic activity of such complexes in ring-closing metathesis (RCM) reactions leading to tetrasubstituted olefins was studied. To obtain quantitative substrate conversion, catalyst loadings of 0.2-0.5 mol% at 80°C in toluene are sufficient. The complex with the best catalytic activity in such RCM reactions and the fastest initiation rate has an NHCewg group with l,3-Me,iPr and 4,5-Cl,Cl substituents and can be synthesized in 95 % isolated yield from the ruthenium precursor. To learn which one of the two NHC ligands acts as the leaving group in olefin metathesis reactions two complexes, [(FL-NHC)-(NHCcwg)RuCl2(CHPh)] and [(FLNHCewg)(NHC)RuCl2(CHPh)], with a dansyl fluorophore (FL)-tagged electron-rich NHC ligand (FL-NHC) and an electron-deficient NHC ligand (FLNHCewg) were prepared. The fluorescence of the dansyl fluorophore is quenched as long as it is in close vicinity to ruthenium, but increases strongly upon dissociation of the respective fluorophore-tagged ligand. In this manner, it was shown for ring-opening metathesis ploymerization (ROMP) reactions at room temperature that the NHCewg ligand normally acts as the leaving group, whereas the other NHC ligand remains ligated to ruthenium.

Facile synthesis of [(NHC)(NHCewg)RuCl2(CHPh)] complexes

The utility of [(NHC)(PPh3)RuCl2(CHPh)] for the facile and efficient synthesis of ten complexes of the type [(NHC)(NHC ewg)RuCl2(CHR)] with saturated and unsaturated NHC ligands in 85-94% isolated yield via a simple one step synthesis utilizing [AgI(NHCewg)] as NHCewg transfer reagents was demonstrated.

Synthesis and RCM activity of [(NHC)(NHCewg)RuCl 2(3-phenylindenylid-1-ene)] complexes

[(NHC)RuCl2(3-phenylindenylid-1-ene)(py)] (1) serves as a convenient starting material for the synthesis of [(NHC)(NHCewg) RuCl2(3-phenylindenylid-1-ene)] complexes 3a-3g utilizing [AgI(NHCewg)] complexes (2) as NHC transfer reagents. The respective complexes 3 display excellent activities in RCM reactions leading to tetrasubstituted olefins. The most active precatalyst, 3f, is characterized by 3,4-dichloro and N,N′-diethyl substituents and can be obtained in 94% isolated yield. The redox potentials of complexes 3 and the crystal structure of 3g (3,4-dichloro and N,N′-diisopropyl substituents) were determined.

An [(NHC)(NHCEWG)RuCl2(CHPh)] complex for the efficient formation of sterically hindered olefins by ring-closing metathesis

NHC with EWGs for RCM: Ruthenium complexes with two N-heterocyclic carbenes (NHCs), one of them substituted with electron-withdrawing groups (EWGs), are highly efficient (pre) catalysts for the synthesis of tetrasubstituted olefins and trisubstituted olef

A hexafluorobenzene promoted ring-closing metathesis to form tetrasubstituted olefins

Highly efficient formation of tetrasubstituted olefins is described by ring-closing metathesis (RCM) using catalyst 2 in presence of hexafluorobenzene. This combination with hexafluorobenzene shows an unexpected promoting effect, which requires low cataly