Synthesis of stable 2H-pyran-5-carboxylates via a catalyzed propargyl-Claisen rearrangement/oxa-6pi electrocyclization strategy.
[reaction: see text] The application of easily accessed propargyl vinyl ethers for the synthesis of monocyclic 2H-pyrans was achieved. Under the reaction conditions, highly substituted heterocycles were obtained in moderate to excellent yields. The one-pot sequence proceeds via a Ag(I)-catalyzed propargyl-Claisen rearrangement, followed by a base-catalyzed isomerization, and 6pi-oxaelectrocyclization, leading to the formation of stable 2H-pyrans.
Menz
Helge
H
Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
Kirsch
Stefan F
SF