Palladium- and Ruthenium-Catalyzed Cycloisomerization of Enynamides and Enynhydrazides: A Rapid Approach to Diverse Azacyclic Frameworks

摘要

Cycloisomerizations are amongst the most atom-economical methods to access valuable organic ring systems from simple acyclic starting materials. 1,n-Enynes have been particularly explored as cycloisomerization substrates, thus giving rise to a broad spectrum of products depending on the choice of catalyst and substrate. In contrast, reports of 1,n-enynamide cycloisomerization are limited to π-acid activation of the ynamide or enynamide ring-closing metathesis. This is surprising given the importance of azacycles in organic and medicinal chemistry, to which enynamide cycloisomerization could provide a unique and sustainable entry.