Unexpected reactivity of pyridinium salts toward alkynyl Fischer complexes to produce<i>oxo</i>‐heterocycles
作者:María Inés Flores‐Conde、Fabiola N. Cruz、Julio López、J. Óscar C. Jiménez‐Halla、Eduardo Peña‐Cabrera、Marcos Flores‐Álamo、Francisco Delgado、Miguel A. Vázquez
DOI:10.1002/aoc.4202
日期:2018.3
The unprecedented reaction of ketone‐containing aromatic pyridiniumsalts 3a‐e and alkynylFischercomplexes 1a‐f proceeds via a mild domino process to provide 4,6‐disubstituted pyran‐2‐ones 5a‐k and 2,3,5‐trisubstituted furans 6a‐h (45‐97%). According of the results of isotopic labeling experiments, a mechanism involving an initial Michael addition appears to be the key step, obtaining a mesomeric