Factors Controlling the Alkyne Prins Cyclization: The Stability of Dihydropyranyl Cations
作者:Pedro O. Miranda、Miguel A. Ramírez、Víctor S. Martín、Juan I. Padrón
DOI:10.1002/chem.200800281
日期:2008.7.7
The relative stability of the intermediates involved in the alkynePrinscyclization and the competitive 2-oxonia-[3,3]-sigmatropic rearrangement was studied. This rearrangement was shown to occur slowly under typical alkynePrinscyclization conditions when the allenyl oxocarbenium ion that results from the rearrangement is similar to or higher in energy than the starting alkynyl oxocarbenium ion
Catalytic One-Pot Synthesis of Cyclic Amidines by Virtue of Tandem Reactions Involving Intramolecular Hydroamination under Mild Conditions
作者:Sukbok Chang、Minjae Lee、Doo Young Jung、Eun Jeong Yoo、Seung Hwan Cho、Sun Kyu Han
DOI:10.1021/ja064788i
日期:2006.9.1
A newsynthetic methodology for the generation of cyclic amidines has been developed by the reaction of 1,n-aminoalkynes with electron-deficient azides using a ruthenium catalyst at ambient temperature. The reaction proceeds most likely via a tandem sequence of intramolecular hydroamination of aminoalkynes, cycloaddition of azides with the resulting enamines, and rearrangement of triazoline intermediates