Brønsted Acid Catalyzed Oxocarbenium-Olefin Metathesis/Rearrangements of 1<i>H</i>-Isochromene Acetals with Vinyl Diazo Compounds
作者:Haifeng Zheng、Kan Wang、Luca De Angelis、Hadi D. Arman、Michael P. Doyle
DOI:10.1021/jacs.1c07271
日期:2021.9.22
2]-cyclization between isobenzopyrylium ions and the vinyl group of vinyl diazoesters, the retro-[2 + 2] cycloaddition produces a tetheredalkene and a vinyl diazonium ion that, upon loss of dinitrogen, undergoes a highly selective carbocationic cascade rearrangements to diverse products whose formation is controlled by reactant substituents. Polysubstituted benzobicyclo[3.3.1]oxocines, benzobicyclo[3.2.2]oxepines
acetylenic aldehydes with alcohols in the presence of a catalytic amount of Pd(OAc)2 in 1,4-dioxane at room temperature gave the 5- or 6-membered acetal products in high yields. The 13C NMR studies suggested that a Pd(II) catalyst exhibited dual roles in the present reaction; the attack of ROH to aldehyde is catalyzed by Lewis acidic Pd(OAc)2, and the nucleophilic oxygen of the resulting hemiacetal reacts
Synthesis of Cyclic Alkenyl Ethers via Intramolecular Cyclization of <i>O</i>-Alkynylbenzaldehydes. Importance of Combination between CuI Catalyst and DMF
作者:Nitin T. Patil、Yoshinori Yamamoto
DOI:10.1021/jo049416b
日期:2004.7.1
remarkably general method for the synthesis of cyclic alkenyl ethersvia the Cu(I)-catalyzed intramolecular cyclization of O-alkynylbenzaldehydes has been developed. The survey of metal catalysts and solvents revealed that the combination of copper(I) iodide and DMF was the catalytic system of choice. The reaction most probably proceeds via the nucleophilic addition of alcohols 2 to O-alkynylbenzaldehydes
Gold-catalyzed tandem cycloisomerization/Petasis–Ferrier rearrangement: a direct route to 3-alkoxyindanones from enynals and alcohols
作者:Ziping Cao、Huaqing Zhang、Xiaoxiang Zhang、Ludan Zhang、Xin Meng、Guang Chen、Xian-En Zhao、Xuejun Sun、Jinmao You
DOI:10.1039/c5ra24541a
日期:——
A method to prepare 3-alkoxyindanones efficiently by gold-catalyzedtandemcycloisomerization/Petasis–Ferrier rearrangement from ortho-ethynylarylaldehydes with alcohols is described. The reaction was accomplished in moderate to excellent yields under mild reaction conditions and also offers a convenient synthetic route to 3-alkoxycyclopentenones.