N-Substituted formamides as nucleophiles react with in situ-generated 1,4-oxazepines from N-propargylic β-enaminones followed by spontaneous N-deformylation to deliver densely substituted 2-aminopyridines in good yields (31–88%). The formyl group is found to be a superior traceless activating group of free amines and would ultimately be removed in situ. This reaction proceeds smoothly at room temperature
Gold-catalysed cyclisation of N-propargylic β-enaminones to form 3-methylene-1-pyrroline derivatives
作者:Kommuru Goutham、N. S. V. M. Rao Mangina、Surisetti Suresh、Pallepogu Raghavaiah、Galla V. Karunakar
DOI:10.1039/c3ob42513d
日期:——
A gold(i) catalysed reaction between N-propargylic β-enaminones and arynes was developed to access 3-methylene-1-pyrrolines. The title compounds were obtained in 57–78% yields.
<scp>Base‐Promoted</scp>
Synthesis of
<scp>3‐Alkenyl</scp>
‐2‐pyridones from
<scp>
<i>N</i>
‐Propargyl
</scp>
‐β‐enaminones and Aryl Aldehydes
作者:Qingyu Tian、Shangyun Xiao、Guolin Cheng
DOI:10.1002/cjoc.202100331
日期:2021.10
In this article, we report a base-promoted sequential cyclization/aldol-type condensation/isomerization cascade reaction of N-propargyl-β-enaminones with aryl aldehydes. The key step in this protocol is the generation of 1,4-oxazepine anions from N-propargyl-β-enaminones under basic conditions, which are captured by aryl aldehydes. The method allows the formation of one pyridone core and one C—C double