Bidentate Lewis Acids for the Activation of 1,2-Diazines - A New Mode of Catalysis
作者:Simon N. Kessler、Markus Neuburger、Hermann A. Wegner
DOI:10.1002/ejoc.201100335
日期:2011.6
BidentateLewisacids were applied as catalysts for the inverse-electron-demand Diels–Alder (IEDDA) reaction of 1,2-diazines. The concept of catalysis is based on the coordination of the bidentateLewisacid to both nitrogen atoms of the 1,2-diazine moiety, thereby reducing the electron density and lowering the energy of the LUMO. This should, according to frontier molecular orbital (FMO) theory, facilitate
Synthesis of Medium-Sized Carbocycles via a Bidentate Lewis Acid-Catalyzed Inverse Electron-Demand Diels–Alder Reaction Followed by Photoinduced Ring-Opening
作者:Julia Ruhl、Sebastian Ahles、Marcel A. Strauss、Christopher M. Leonhardt、Hermann A. Wegner
DOI:10.1021/acs.orglett.1c00249
日期:2021.3.19
The combination of a Lewis acid-catalyzed inverseelectron-demandDiels–Alder (IEDDA) reaction with a photoinduced ring-opening (PIRO) reaction in a domino process has been established as an efficient synthetic method to access medium-sized carbocycles. From readily available electron-rich and electron-poor phthalazines and enamines, respectively, as starting materials, various 9- and 11-membered carbocycles
Nickel-catalyzed cocyclotrimerization of arynes with diynes; a novel method for synthesis of naphthalene derivatives
作者:Jen-Chieh Hsieh、Chien-Hong Cheng
DOI:10.1039/b415691a
日期:——
The NiBr2(dppe)–Zn system effectively catalyzes the [2 + 2 + 2] cocyclotrimerization of arynes with diynes, leading to substituted naphthalene derivatives in moderate to good yields. This cocyclotrimerization reaction shows excellent tolerance of functional groups and leads to products of 5- to 7-membered fused-ring sizes
An efficient cationic cyclization reaction has been developed to prepare substituted naphthalenes. The method has been used to prepare a phenanthrene and will be useful for the synthesis of polynucleararomatichydrocarbons and C-glycosyl anthraquinones.
The [5]metacyclophane derivative (3) was obtained in 55% isolated yield by treatment of (2) with silver perchlorate in the presence of 2,6-lutidine in tetrahydrofuran solution; (3) isomerizes to (6) in acidic solution and is converted by hydrogen bromide in benzene–acetic acid–water into a mixture consisting mainly of (6), (8a), and (8b).