AbstractAromatic enynes can be transformed into arylnaphthalenes or benzofulvenes depending on the reaction conditions. Under gold(I) catalysis, exclusive or major 6‐endo‐dig cyclization took place leading to arylnaphthalenes. However, a catalytic system based on palladium iodide/1,3‐bis(diphenylphosphino)propane, in the presence of cesium carbonate as a base was necessary to furnish exclusively 5‐exo‐dig cyclization pattern, regardless of the electronic effects of the substituents. In the latter transformation, a mechanistic study (kinetic isotopic effect, density functional theory) involving a CH activation is suggested for the exclusive formation of benzofulvenes.magnified image
ruthenium‐catalyzed carbocyclization of 2‐alkynylstyrenes that involves a very rare 1,2‐carbon migration of internal alkynes is reported. Various 1,2‐di ‐and 1,4,7‐trisubstituted naphthalenes are synthesized. Mechanistic studies revealed that this reaction proceeds via a disubstituted vinylidene complex as the key intermediate by 1,2‐carbon migration of the 2‐alkynylstyrenes.
Palladium-Catalyzed Aerobic Oxidative Coupling of <i>ortho</i>-(Alkynyl)styrenes with Allylic Alcohols via 6-<i>endo-dig</i> Cyclization: Regioselective Construction of Polysubstituted Naphthalenes
作者:Perla Ramesh、Gedu Satyanarayana
DOI:10.1021/acs.joc.9b01240
日期:2019.10.18
An efficient protocol is described for the regioselective construction of polysubstituted functionalized naphthalenes from easily accessible ortho-(alkynyl)styrenes under mild reaction conditions. The reaction proceeds via cycloaromatization and intermolecular coupling of ortho-(alkynyl)styrenes with allylicalcohols catalyzed by PdCl2. Notably, the reaction is successful under open air as the green
A Pd(II)-catalyzed mild and highly regioselective 6-endo cyclization/alkylation reaction of o-(alkynyl)styrenes with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after cyclization could insert a C-C double bond of allylic alcohol through a cross-coupling reaction and led to the formation of (alkyl)naphthalenes. This cascade
An efficient electrochemical synthesis of sulfonated phenanthrenes via the reaction of internal alkynes with sulfonyl hydrazides has been established. The protocol does not require a metal catalyst or external oxidants, providing a green and mild route to functionalized phenanthrenes. Moreover, the compatibility of various functional groups and decagram-scale experimental conditions demonstrate the
Palladium-Catalyzed Bisolefination of C−C Triple Bonds: A Facile Method for the Synthesis of Naphthalene Derivatives
作者:Chao Feng、Teck-Peng Loh
DOI:10.1021/ja108998d
日期:2010.12.22
A highly efficient and mild palladium-mediated bisolefination of C-C triple bonds is described for the first time. With different types of olefin employed, this reaction terminates in diverse fashions. In addition to the merit of using oxygen as the sole oxidant, this reaction exhibits high reactivities and functionality tolerance simultaneously, thus providing a promising method for the synthesis of naphthalene derivatives.