[3,3]-Sigmatropic rearrangements of propargyl alkynyl ethers. Synthesis of complex dienoates and unsaturated lactones
Juan R Sosa1, Armen A Tudjarian1, Thomas G Minehan1
1Department of Chemistry and Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330-8262, US. thomas.minehan@csun.edu.
Abstract:
In an extension of our studies on low-temperature rearrangements of 1-alkynyl ethers, we describe herein the [3,3]-sigmatropic rearrangement of in situ formed propargyl alkynyl ethers to allenyl ketenes, which furnish complex tert-butyl-(2E,4Z)-dienoates 2 in good yields upon tert-butanol addition. Similarly, sigmatropic rearrangements of in situ formed propargyl lithioalkynyl ethers yield methyl-(2Z,4Z)-dienoates 4 upon methanol addition or unsaturated lactones 6 upon aldehyde or ketone addition to the allenyl ynolate intermediate.
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