azaheterocycle N-oxides with alkenes catalyzed by iodine under metal- and external oxidant-free reaction conditions has been developed. A variety of (E)-2-styrylazaheterocycles have been produced in moderate to excellent yields. The mechanistic exploration indicated that the N-oxide group played dual roles as both the directing group and an internal oxidant in this catalytic cycle.
A direct C–H/P–H functionalization of heteroaryl N-oxides with H-phosphonates under metal and oxidant free conditions was developed. Various heteroaryl phosphonate derivatives were obtained in up to 92% yield in a chemo- and regioselective manner.
Catalytic Selective Metal-Free Cross-Coupling of Heteroaromatic <i>N</i>-Oxides with Organosilanes
作者:Mahesh Puthanveedu、Vasiliki Polychronidou、Andrey P. Antonchick
DOI:10.1021/acs.orglett.9b01141
日期:2019.5.3
of heteroaromatic N-oxides has been developed. The method enables the synthesis of various benzylated and alkynylated N-heterocycles in a transition-metal-free manner employing organosilanes as coupling partners. The unanticipated reactivity has been exploited for the synthesis of a number of symmetrical disubstitutedacetylenes from ethynyltrimethylsilane via carbon–silicon bond metathesis.
Facile Route to 2-Fluoropyridines via 2-Pyridyltrialkylammonium Salts Prepared from Pyridine <i>N</i>-Oxides and Application to <sup>18</sup>F-Labeling
作者:Hui Xiong、Adam T. Hoye、Kuo-Hsien Fan、Ximin Li、Jennifer Clemens、Carey L. Horchler、Nathaniel C. Lim、Giorgio Attardo
DOI:10.1021/acs.orglett.5b01703
日期:2015.8.7
Among known precursors for 2-[18F]fluoropyridines, pyridyltrialkylammonium salts have shown excellent reactivity; however, their broader utility has been limited because synthetic methods for their preparation suffer from poor functional group compatibility. In this paper, we demonstrate the regioselective conversion of readily available pyridine N-oxides into 2-pyridyltrialkylammonium salts under mild
A new protocol for the enantioselective direct α-heteroarylation of aldehydes with isoquinoline N-oxides, via chiral enamine catalysis, has been successfully developed. High enantiomeric excesses and moderate to good yields were achieved for a variety of α-heteroarylated aldehydes.