作者:Gyula Simig、Gábor Doleschall、Gyula Hornyák、József Fetter、Károly Lempert、József Nyitrai、Péter Huszthy、Tibor Gizur、Mária Kajtár-Peredy
DOI:10.1016/s0040-4020(01)96442-7
日期:1985.1
of the ethylene ketals 7a–7d of the latter furnishes mixtures of the corresponding diastereomeric monoesters 8 and10. The ethoxycarbonyl groups of the trans esters 8 are more reactive than those of the cis isomers 10. This permits, under appropriate conditions, selective alkaline hydrolysis and NaBH4 reduction of the trans esters 8 in the presence of the cis esters 10. Reduction of the cis ester 10c
N-取代的氨基丙二酸二乙酯3a - 3d与双烯酮的酰化作用提供了预期的乙酰乙酰基衍生物5的环互变异构体6a - 6d。通过用碘和乙醇钠处理,化合物6a - 6d可以平稳地转化为β-内酰胺衍生物2a - 2d。后者的乙烯缩酮7a - 7d的脱氧羰基羰基化反应提供了相应的非对映体单酯8和10的混合物。反酯8的乙氧羰基比顺式异构体10具有更高的反应性。这允许在合适的条件下,在顺式酯10的存在下选择性地碱水解和反式酯8的NaBH 4还原。在更强力的条件下还原顺式酯10c提供了反式羟甲基衍生物11c。