159991-80-7Relevant academic research and scientific papers
Auxiliary Accelerated Reactions: Transition-metal Promoted Diels-Alder Cycloadditions
Westwell, Andrew D.,Williams, Jonathan M. J.
, p. 2501 - 2502 (1994)
Rate enhancements for the Diels-Alder reaction of (2-pyridyl)methyl propenoate 2 over benzyl propenoate 1 are observed in the presence of transition-metal promoters, particularly copper(II) and zinc(II) triflate.
Oxathiaborolium-Catalyzed Enantioselective [4 + 2] Cycloaddition and Its Application in Lewis Acid Coordinated and Chiral Lewis Acid Catalyzed [4 + 2] Cycloaddition
Boobalan, Ramalingam,Chein, Rong-Jie
supporting information, p. 6760 - 6764 (2021/09/11)
The nascency of second-generation sulfur-stabilized borenium cations by halophilic Lewis acid SnCl4 leads to highly active chiral Lewis acids that are very effective catalysts for [4 + 2] cycloaddition. Oxathiaborolium pentachlorostannate (5-10 mol %) successfully catalyzed cycloaddition of various dienes and dienophiles to afford cycloadducts with excellent enantioselectivity (20 examples, up to 99% ee). This super Lewis acid also exhibited good enantioselectivity for the first Lewis acid coordinated and chiral Lewis acid catalyzed [4 + 2] cycloaddition to α,β-unsaturated mixed ester amide.
In situ generated "lanthanum(iii) nitrate alkoxide" as a highly active and nearly neutral transesterification catalyst
Hatano, Manabu,Kamiya, Sho,Ishihara, Kazuaki
supporting information, p. 9465 - 9467 (2012/10/29)
In situ generated lanthanum(iii) nitrate alkoxide is a highly active and nearly neutral transesterification catalyst, which can promote non-epimerized transesterification of α-substituted chiral carboxylic esters under reflux conditions.
Stabilization of a kinetically favored nanostructure: Surface ROMP of self-assembled conductive nanocoils from a norbornene-appended hexa-peri-hexabenzocoronene
Yamamoto, Takuya,Fukushima, Takanori,Yamamoto, Yohei,Kosaka, Atsuko,Jin, Wusong,Ishii, Noriyuki,Aida, Takuzo
, p. 14337 - 14340 (2008/03/13)
Newly designed norbornene-appended hexabenzocoronene 1 self-assembles, upon diffusion of an Et2O vapor into its CH2Cl2 solution, to form either graphitic nanocoils or nanotubes, depending on the self-assembling conditions. The coiled assembly, selectively formed at 15 °C, is a kinetic intermediate for the tubular assembly and transforms into nanotubes on standing at 25 °C. However, post-ring-opening metathesis polymerization of the norbornene pendants of 1 enhances the thermal stability of the coiled assembly as well as the tubular one and disables a thermodynamic coil-to-tube transition. The polymerized nanocoils show an electroconductivity of 1 × 10-4 S cm-1 upon doping with I2, while the nonpolymerized nanocoils are disrupted upon being doped.
Auxiliary accelerated reactions: Towards the use of catalytic chiral auxiliaries
Westwell, Andrew D.,Williams, Jonathan M. J.
, p. 13063 - 13078 (2007/10/03)
In competition experiments, the acceleration of reactivity of alkenes tethered to pyridyl groups compared with the corresponding alkenes tethered to phenyl groups in the presence of transition metals was demonstrated for two reaction types: Diels-Alder cycloaddition of enoate esters and catalytic hydrogenation of allylic and homoallylic ethers. The rate accelerations observed are of crucial importance in the development of a new concept for asymmetric catalysis: chiral auxiliaries which can function in a catalytic manner.
