34815-65-1

Upstream product

• 5398-04-9 2-(4-methoxyphenyl)-2-butanol 
• 622-97-9 1-ethenyl-4-methylbenzene 
• 74-85-1 ethene 
• 1195-32-0 1-methyl-4-isopropenylbenzene 
• 21758-18-9 4-methyl-α-ethylstyrene 
• 122-00-9 para-methylacetophenone 
• 87959-45-3 1-(2,2-dibromo-1-methylcyclopropyl)-4-methylbenzene 
• 4294-57-9 para-methylphenylmagnesium bromide 

Relevant academic research and scientific papers

Iron Catalyzed Isomerization of α-Alkyl Styrenes to Access Trisubstituted Alkenes

Stereoselective isomerization of α-alkyl styrenes is accomplished using a new iron catalyst supported by phosphine-pyridine-oxazoline (PPO) ligand. The protocol provides an atom-efficient and operationally simple approach to trisubstituted alkenes in high

Method for stereoselective synthesis of (E)-trisubstituted olefin

Belonging to the technical field of metal catalytic synthesis, the invention discloses a method for stereoselective synthesis of (E)-trisubstituted olefin. The method includes: taking 1, 1-disubstituted olefin as the raw material, and adopting a combination of CoX2 and PAO ligand as the catalyst; and in the presence of an activating reagent, carrying out reaction for 0.5min-48h at a temperature ranging from -30DEG C to 80DEG C to prepare (E)-trisubstituted olefin. Compared with the prior art, the method has the advantages of more economical, efficient and environment-friendly catalyst, good tolerance of the reaction functional group, mild reaction conditions, simple operation, no need for participation of additional reagents, and atom economy of 100%. In addition, the reaction has no needof any other toxic transition metal (like ruthenium, rhodium, palladium, etc.) salt, therefore the method has great practical application value in pharmaceutical and food chemical industry.

Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes

Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.

Cobalt-Catalyzed Migrational Isomerization of Styrenes

An efficient cobalt-catalyzed migrational isomerization of styrenes was developed using the thiazoline iminopyridine (TIP) ligand. This reaction is operationally simple and atom-economical using readily available starting materials to access trisubstituted alkenes. Even when using a 0.1 mol % catalyst loading, the reaction could be conducted in neat and completed in 1 h with excellent conversion and high E stereoselectivity.

Regioselective Diboron-Mediated Semireduction of Terminal Allenes

A method for the regioselective reduction of the terminal double bond of 1,1-disubstituted allenes has been developed. In the presence of a palladium catalyst, tetrahydroxydiboron and stoichiometric water, allene semireduction proceeds in high yield to afford Z-alkenes selectively.

Iron catalyzed methylation and ethylation of vinyl arenes

Short alkyl chain Heck (type) reactions, especially methyl Heck reactions, are a difficult aspect of the alkyl Heck reaction. To provide a solution to this problem, iron-catalyzed methyl, ethyl and propyl Heck reactions were developed using readily available alkyl peroxides as alkyl sources. The reaction conditions were mild, clean, and easy to handle. No additive was needed, and no hazardous waste was generated. The products were obtained in up to 99% yield of one isomer for most situations. This reaction works for many types of olefin and tolerates a variety of functional groups. Several late-stage functionalizations of natural products and drug molecules were conducted to demonstrate the synthetic applications of this reaction.

Triarylphosphine ligands with hemilabile alkoxy groups: Ligands for nickel(II)-catalyzed olefin dimerization reactions. hydrovinylation of vinylarenes, 1,3-dienes, and cycloisomerization of 1,6-dienes

Substitution of one of the phenyl groups of triphenylphosphine with a 2-benzyloxy-, 2-benzyloxymethyl- or 2-benzyloxyethyl-phenyl moiety results in a set of simple ligands, which exhibit strikingly different behaviour in various nickel(II)-catalyzed olefin dimerization reactions. Complexes of ligands with 2-benzyloxyphenyl- and 2-benzyloxymethylphenyldiphenylphosphine (L5 and L6, respectively) are most active for hydrovinylation (HV) of vinylarenes, with the former leading to extensive isomerization of the primary 3-aryl-1-butenes into the conjugated 2-aryl-2-butenes even at -55 °C. However, 2-benzyloxymethyl-substituted ligand L6 is slightly less active, affording up to quantitative yields of the primary products of HV at ambient temperature with no trace of isomerization, thus providing the best option for a practical synthesis of these compounds. In sharp contrast, hydrovinylation of a variety of 1,3-dienes is best catalyzed by nickel(II) complexes of 2- benzyloxyphenyldiphenylphosphine, L5. The other two ligands, 2-benzyloxymethyl- (L6) and 2-benzyloxyethyldiphenylphosphine (L7) are much less effective in the HV of 1,3-dienes. Nickel(II)-catalyzed cycloisomerization of 1,6-dienes into methylenecyclopentanes, a reaction mechanistically related to the other hydrovinylation reactions, is also uniquely effected by nickel(II) complexes of L5, but not of L6 or L7. In an attempt to prepare authentic samples of the methylencyclohexane products, nickel(II) complexes of N-heterocyclic carbene ligands were examined. In sharp contrast to the phosphines, which give the methylenecyclopentanes, methylenecyclohexanes are the major products in the (N-heterocyclic carbene)nickel(II)-mediated reactions.