31382-76-0Relevant academic research and scientific papers
Axially Chiral 1,1'-Binaphthyl-2-Carboxylic Acid (BINA-Cox) as Ligands for Titanium-Catalyzed Asymmetric Hydroalkoxylation
Blazejak, Max,Helmbrecht, Sebastian L.,Hintermann, Lukas,Schlüter, Johannes
supporting information, (2020/04/15)
Axially chiral, enantiopure 1,1'-binaphthyl-2-carboxylic acids (BINA-Cox) have recently been introduced as chiral ligands for transition metal catalysis. Together with equimolar, co-catalytic amounts of Ti(OiPr)4 and water they form an in situ catalyst that performs the asymmetric catalytic hydroalkoxylation of 2-allylphenols to 2-methylcoumarans at high temperature (240 °C, microwave heating). The synthesis of reference ligand 2'-MeO-BINA-Cox (L1) has been optimized and performed at molar scale. Synthetic routes have been developed to access a variety of substituted BINA-Cox ligands (>30 examples), which have been tested for ligand effects on the reference asymmetric cyclization of 2-allylphenol. The substrate range of asymmetric catalytic hydroalkoxylation has been explored through systematic substrate structure variations to define scope and limitations of the titanium-catalyzed process. The new substrates 2-(1-vinylcycloalkyl)phenols (1j, 1k), 2-(2-vinylphenyl)propan-2-ol (1t), and 2'-vinyl-[1,1'-biphenyl]-2-ol (1u) are shown to undergo asymmetric catalytic cyclization to benzodihydrofurans and benzo[c]chromene, respectively.
Living anionic polymerization of 4-(α-alkylvinyl)styrene derivatives
Hirao, Akira,Imai, Takahiro,Watanabe, Kenji,Hayashi, Mayumi,Sugiyama, Kenji
, p. 855 - 867 (2007/10/03)
The anionic polymerization of four bis-functionalized styrene derivatives with α-alkylvinyl groups have been carried out in THF at -78°C with the initiator prepared from oligo(α-methylstyryl)lithium and potassium tert-butoxide. The four monomers herein us
Catalyzed intramolecular olefin insertion into a carbon-carbon single bond
Murakami, Masahiro,Itahashi, Tamon,Ito, Yoshihiko
, p. 13976 - 13977 (2007/10/03)
Intramolecular insertion of a C-C double bond into a C-C single bond was achieved by treatment of cyclobutanone bearing an o-styryl group at the 3-position with a catalytic amount of a cationic rhodium(I)-dppp complex. Initially, rhodium is inserted betwe
Photochemistry of 3-methyl- and 4-methyl-1,2-dihydronaphthalene in the gas phase1
Duguid, Robert J.,Morrison, Harry
, p. 1271 - 1281 (2007/10/02)
The photochemistry of 3-methyl-1,2-dihydronaphthalene (3-MDHN) and 4-methyl-1,2-dihydronaphthalene (4-MDHN) has been studied in the gas phase. Photolysis of 3-MDHN with 254-nm light produces 2-methyl-1,2-dihydronaphthalene (2-MDHN) as the major primary product. Naphthalene is also formed, apparently as a secondary photoproduct from 2-MDHN. Addition of butane to the photolysis mixture quenches the formation of 2-MDHN while producing a new photoproduct, 1-isopropenylbenzocyclobutene (IBCB). This product is also formed when light centered at 300 nm is used for the photolysis. Photolysis of 4-MDHN vapor with 254-nm light gives three products unique to the gas phase: 1-isopropenyl-2-vinylbenzene (IVB), 3-(o-tolyl)-1,2-butadiene (T12B), and 1-methyl-1,2-dihydronaphthalene (1-MDHN). An apparent alkyl shift product, 3-methyl-1,2-dihydronaphthalene (3-MDHN), and naphthalene are also formed, apparently as secondary photolysis products from 1-MDHN. In addition, several photoproducts common to both the solution and gas phase are detected: 2-(o-tolyl)-1,3-butadiene (T13B), 1-methylbenzobicyclo[3.1.0]hex-2-ene (1-MBBH), 1-methyl-1,4-dihydronaphthalene (1-M-1,4-DHN), 1-methyltetralin (1-MT), and 1-methylnaphthalene (1-MN). Again, the presence of butane during the 254-nm photolysis, or the use of longer wavelength light, gives rise to a new photoproduct, 1-methyl-1-vinylbenzocyclobutene (MVBCB). The fluorescence excitation spectrum for 4-MDHN confirms that 254-nm excitation into S2 leads to minimal population of the emissive vibrational levels of S1. Two pathways appear to dominate the photochemistry: retro [4 + 2] cycloaddition to give o-quinodimethane intermediates and sequential hydrogen shifts. These pathways derive from S2 and/or upper vibrational levels of S1 (S1vib) as indicated by the characteristic responses of their ultimate products to the presence of buffer gas. The benzocyclobutenes are unique; they are postulated to arise through a 2 + 2 closure of a vibrationally relaxed precursor o-quinodimethane or via a [1,3] sigmatropic shift in a uniquely populated set of S1vib levels.
