New route to 1,3,3a,8a-tetrahydro-2H-benzofuro[2,3-b]pyrrol-2-ones from methyl α-hydroxy-4H-1,2-benzoxazine-4-acetates obtained by ring transformation of 4-aryl-2-isoxazoline 2-oxides

Article abstract of DOI:10.1248/cpb.42.1562

4-Aryl-2-isoxazoline 2-oxides (1) were converted to methyl α-hydroxy-3-methoxycarbonyl-4H-1,2-benzoxazine-4-acetates (3) upon treatment with a Lewis acid such as titanium tetrachloride. The structure of 3 was confirmed by X-ray analysis. Tosylates of 3 were treated with triethylamine to yield (E)- and (Z)-isomers of olefins (5) with (E)-preference. Catalytic reduction of each isomer of 5 produced 5,8a-disubstituted 1,3,3a,8a-tetrahydro-2H-benzofuro[2,3-b]pyrrol-2-ones (6) in moderate yields.

Full text of DOI:10.1248/cpb.42.1562

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NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service