Intermolecular Homopropargyl Alcohol Addition to Alkyne and a Sequential 1,6-Enyne Cycloisomerization with
Seyedmorteza Hosseyni1, Lukasz Wojtas1, Minyong Li2
1Department of Chemistry, University of South Florida , Tampa, Florida 33620, United States.
Abstract:
While gold-catalyzed homopropargyl alcohol cyclization is a known process, a triazole-gold catalyst prevented the intramolecular cyclization in the presence of terminal alkynes. As a result, an intermolecular addition to an alkyne was achieved. A sequential 1,6-enyne cycloisomerization gave the unusual 2,3-dihydrooxepine, which revealed another new reaction path. Diels-Alder reaction of oxepine followed by a 1,3-alkoxyl shift gave hydrobezofuran derivatives in high yields. Diasterioselective reaction of homopropargyl alcohol to final product enabled one-step formation of five stereogenic centers with excellent enantiomeric selectivity.
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