Monohydrochloride Assisted Synthesis of Functionalized Isoxazoles and Pyrazoles from Allenic Ketones: First Synthesis of (<i>Z</i>
)-2-Methyl-7H-benzo[b]pyrazolo[5,1-d][1,5]oxazocines
作者:Debayan Sarkar、Sushree Ranjan Sahoo
DOI:10.1002/ejoc.201900008
日期:2019.3.14
A straight forward synthesis of substituted isoxazoles and pyrazoles from 1,2‐allenic ketones assisted by hydrochlorides of hydrazine and hydroxylamine is presented. In the process, the propyloxy‐phenyl pyrazoles were transformed to (Z)‐2‐methyl 7H benzo[b]pyrazolo[5,1‐d][1,5]oxazocines which are important and emissive compounds.
Allenyl Ketones as Versatile Michael Acceptors for the Addition of Chelated Enolates
作者:Uli Kazmaier、Simon Lucas
DOI:10.1055/s-2005-923591
日期:——
Chelated amino acid ester enolates undergo clean 1,4-addition towards allenyl ketones 9, giving rise to unsaturated δ-keto amino acid esters 12 at low temperature. If the reaction is allowed to warm to room temperature, the enolate intermediates A undergo cyclization towards the corresponding α-pyrones 13.
Au nanoparticlessupported on TiO2 (1 mol %) catalyze the quantitative cycloisomerization of conjugated allenones into furans under very mild conditions. The reaction rate is accelerated by adding acetic acid (1 equiv), but the acid does not participate in the protodeauration step as in the corresponding Au(III)-catalyzed transformation. The process is purely heterogeneous, allowing thus the recycling
Tunable Synthesis of Functionalized Cyclohexa-1,3-dienes and 2-Aminobenzophenones/Benzoate from the Cascade Reactions of Allenic Ketones/Allenoate with Amines and Enones
作者:Tian Feng、Miaomiao Tian、Xinying Zhang、Xuesen Fan
DOI:10.1021/acs.joc.8b00473
日期:2018.5.4
TEMPO-dependent tunable synthesis of functionalized cyclohexa-1,3-dienes and 2-aminobenzophenones/benzoate from the one-pot cascade reactions of allenic ketones/allenoate with amines and enones is presented. Mechanistically, the construction of the entitled six-membered carbocycles involves the in situ generation of an enaminone intermediate via the conjugate addition of allenic ketone with amine followed
An efficientsynthesis of substituted indolizine and its benzo derivatives, pyrrolo[1,2-a]quinolines and pyrrolo[2,1-a]isoquinolines, by the reaction of allenyl ketones with α-bromo carbonyl compounds and pyridines (quinoline or isoquinoline) under mild conditions without an added oxidant other than molecular oxygen from air was developed. Notably, allenyl ketones with or without a substituent attached