An efficient approach has been described for the synthesis of 3,5-disubstituted isoxazoles from propargylic alcohols. The strategy involves a one-pot p-TSA-catalyzed N-propargylation of protected hydroxylamines followed by a TBAF-mediated detosylative 5-endo-dig cyclization. The method was successfully used for the synthesis of various 3,5-disubstituted isoxazoles.
Selective Oxidation of Propargylic Alcohols into α,β-Acetylenic Aldehydes with a TiCl4/Et3N System
作者:Zhenfu Han、Hiroshi Shinokubo、Koichiro Oshima
DOI:10.1055/s-2001-16807
日期:——
A TiCl4/Et3N combination proved to be effective for the selective oxidation of propargylic alcohols into α,β-acetylenic aldehydes in good yields. Treatment of 2-hexyne-1,6-diol with TiCl4/Et3N provided 6-hydroxy-2-hexynal in good yield.
Kinetic or Dynamic Control on a Bifurcating Potential Energy Surface? An Experimental and DFT Study of Gold-Catalyzed Ring Expansion and Spirocyclization of 2-Propargyl-β-tetrahydrocarbolines
control the selectivity is still not fully examined. This missing link in transition state theory is founded in the present study. Aiming to develop new methods for the synthesis of azocinoindole derivatives, we found that 2-propargyl-β-tetrahydrocarbolines can undergo ring expansion and spirocyclization under gold catalysis. DFT study revealed that the reaction starts with the intramolecular cyclization
On the Palladium(II)-Catalysed Oxidative Rearrangement of Propargylic Acetates
作者:A. Bartels、R. Mahrwald、K. Müller
DOI:10.1002/adsc.200303200
日期:2004.3
The catalytic transformation of propargylic acetates into the corresponding α-acetoxyenones in the presence of palladium(II) chloride is described. Water is a necessary component in this unusual oxidative rearrangement.
Rhenium-catalyzed Coupling of 2-Propynyl Alcohols and Several Nucleophiles via Dehydration
作者:Yoichiro Kuninobu、Hirokazu Ueda、Kazuhiko Takai
DOI:10.1246/cl.2008.878
日期:2008.8.5
Treatment of 2-propynyl alcohols with several nucleophiles in the presence of a catalytic amount of a rhenium complex, [ReBr(CO)3(thf)]2, gave coupling products via dehydration. In these reactions, C–C, C–O, and C–S bonds can be constructed under mild conditions.