REARRANGEMENT OF 2, 3-DIOXO-1, 4-OXAZINES TO 4, 5-DIOXOOXAZOLES IN THE REACTION WITH DIMETHYLSULFOXONIUM METHYLIDE

Jun TODA; Masaharu SEKI; Kazuko AMANO; Taichi OYAMA; Takehiro SANO; Fumiyuki KIUCHI; Yoshisuke TSUDA

doi:10.1248/cpb.42.739

Jun TODA, Masaharu SEKI, Kazuko AMANO, Taichi OYAMA, Takehiro SANO, Fumiyuki KIUCHI, Yoshisuke TSUDA

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Keywords: 2, 3-dioxo-2, 3-dihydro-4H-1, 4-oxazine, dimethylsulfoxonium methylide, 4, 5-dioxo-2, 3, 4, 5-tetrahydrooxazole, ring contraction, methylenation

JOURNAL FREE ACCESS

1994 Volume 42 Issue 3 Pages 739-741

DOI https://doi.org/10.1248/cpb.42.739

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Abstract

Reaction of 2, 3-dioxo-2, 3-dihydro-4H-1, 4-oxazines 2a-e with dimethylsulfoxonium methylide introduced an exo-methylene group with concomitant ring contraction to give 4, 5-dioxo-2, 3, 4, 5-tetrahydrooxazoles 3a-e in moderate yields. Mechanism of this unusual reaction was discussed.

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