A modified Kondrat’eva cycloaddition involving an unprecedented thermally controlled metal-free decarboxylative aromatization affords an expedient access to natural 3-hydroxypyridine/piperidine systems.
Metal-Free Decarboxylative Hetero-Diels–Alder Synthesis of 3-Hydroxypyridines: A Rapid Access to <i>N</i>-Fused Bicyclic Hydroxypiperidine Scaffolds
作者:Laurie-Anne Jouanno、Vincent Di Mascio、Vincent Tognetti、Laurent Joubert、Cyrille Sabot、Pierre-Yves Renard
DOI:10.1021/jo402729a
日期:2014.2.7
A complete experimental and theoreticalstudy of the thermally controlled metal-free decarboxylative hetero-Diels–Alder (HDA) reaction of 5-alkoxyoxazoles with acrylic acid is reported. This strategy offers a new entry to valuable 2,6-difunctionalized 3-hydroxypyridines from readily available 2- and 4-disubstituted 5-alkoxyoxazoles. The reaction conditions proved compatible with, among others, ketone
A general and single-step access to polysubstituted 3-hydroxypyridine scaffolds via hetero-DielsâAlder (HDA) reactions between readily prepared 5-ethoxyoxazoles and dienophiles is reported. The HDA reaction, run in the presence of Nd(OTf)3 at room temperature, was successfully applied to various 5-ethoxyoxazoles showing good functional group tolerance, and led to a straightforward process to obtain useful building-blocks.
Synthesis of Cyclic β-Silylalkenyl Triflates via an Alkenyl Cation Intermediate
作者:Craig J. Lee、Manisha Swain、Ohyun Kwon
DOI:10.1021/acs.orglett.8b02398
日期:2018.9.7
Trimethylsilylalkyne derivatives are transformed into cyclic β-silylalkenyl triflates through cationic cyclization and subsequent trapping of the alkenyl cation by a triflate anion. β-Silylcyclohexenyl triflates and 3-trimethylsilyl-1,4-dihydronaphth-2-yl triflates are generated efficiently using this methodology. These products provide ready access to substituted cyclohexynes, exemplified by a concise
reactions are largely underrepresented in the toolbox of chemoselective ligations despite their tremendous potential, particularly in chemical biology and biochemistry. In this respect, we have investigated in full detail the fluorescence behaviour of the azaphthalamide, a scaffold which is generated through a hetero‐Diels–Alder reaction of 5‐alkoxyoxazole and maleimide derivatives under mild conditions