Ruthenium-Catalyzed, Microwave-Mediated [2+2+2] Cycloaddition: A Useful Combination for the Synthesis of 2-Aminopyridines
作者:C. Tran、M. Haddad、V. Ratovelomanana-Vidal
DOI:10.1055/s-0037-1611920
日期:2019.10
A ruthenium-catalyzed [2+2+2] cycloaddition between α,ω-diynes and cyanamides is reported under microwave irradiation to access 2-aminopyridines. In contrast to the classical thermal conditions, this atom-economical sustainable protocol allows access to diverse functionalized 2-aminopyridine derivatives with high yields and excellent regioselectivities in MeTHF with short reaction times.
A practical and mild process to access 2-aminopyridine derivatives using ruthenium-catalyzed [2+2+2] cycloaddition of various 1,6- and 1,7-diynes with cyanamides is described. This straightforward atom-economical catalytic cycloaddition is scalable and showed excellent regioselectivities to approach a wide range of 2-aminopyridines of high synthetic utility. Postfunctionalization reactions of halo-containing
Gold(I)-Catalyzed Cascade Cyclization of Anilines with Diynes: Controllable Formation of Eight-Membered Ring-Fused Indoles and Propellane-Type Indolines
Heterocycle-fused indoles or indolines are distributed widely in a variety of natural products, bioactive agents, and pharmaceuticals. Herein, we describe the development of gold-catalyzed cascade reactions of anilines with diynes to form eight-membered ring-fused indoles and propellane-type indolines, both of which proceed through an intramolecular 5-endo-dig hydroamination followed by an 8-endo-dig
efficient protocol was developed for the synthesis of carboxylic acids, esters, and amides through oxidation of alkynyl boronates, generated directly from terminal alkynes. This protocol represents the first example of C(sp)−B bond oxidation. This approach displays a broad substrate scope, including aryl and alkyl alkynes, and exhibits excellent functionalgroup tolerance. Water, primary and secondary
Mechanism‐Based Approach to Reagent Selection for Oxidative Carbon−Hydrogen Bond Cleavage Reactions
作者:Jenna L. Miller、Lin Zhou、Peng Liu、Paul E. Floreancig
DOI:10.1002/chem.202103078
日期:2022.1.3
Selecting the optimal reagent for an oxidative C−H cleavage reaction requires mechanistic understanding of these processes. This manuscript describes an experimental approach to identify the role of substrate oxidation potential, cation stability, and steric factors on reaction rates and yields with common oxidants. The results are explained through computational transition state energetic and geometric