Expeditious Syntheses of Conjugated Allenyl Esters and Oxazoles through a Cascade Reaction of α-Alkynyl Malonates under Alkaline Conditions

Shigeki Sano; Hisashi Shimizu; Kweon Kim; Woo Song Lee; Motoo Shiro; Yoshimitsu Nagao

doi:10.1248/cpb.54.196

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Expeditious Syntheses of Conjugated Allenyl Esters and Oxazoles through a Cascade Reaction of α-Alkynyl Malonates under Alkaline Conditions

Shigeki Sano, Hisashi Shimizu, Kweon Kim, Woo Song Lee, Motoo Shiro, Yoshimitsu Nagao

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Keywords: conjugated allenyl ester, oxazole, α-alkynyl methoxymalonate, α-alkynyl acetylaminomalonate, hydrolysis, decarboxylation

JOURNAL FREE ACCESS

2006 Volume 54 Issue 2 Pages 196-203

DOI https://doi.org/10.1248/cpb.54.196

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Abstract

Diethyl α-alkynyl-α-methoxymalonates (2a—e) were smoothly hydrolyzed and then decarboxylated under alkaline conditions employing 1 N KOH in EtOH to give conjugated allenyl esters (6a—e) in high yields, and similar alkaline treatment of diethyl α-alkynyl-α-acetylaminomalonates (5a, b, d, e) furnished unexpectedly the oxazoles (7a, b, d, e) having three substituent groups in excellent yields.

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