METHYLENOMYCIN-B - NEW SYNTHESES BASED ON BETA-KETO AND GAMMA-KETO PHOSPHONATES AND GAMMA-KETO PHOSPHINE OXIDES

被引:37
作者
MIKOLAJCZYK, M
ZATORSKI, A
机构
[1] Center of Molecular and Macromolecular Studies, Polish Academy of Sciences, Department of Organic Sulfur Compounds, Sienkiewicza 112
关键词
D O I
10.1021/jo00003a051
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Methylenomycin B has been synthesized from diethyl 2-oxobutanephosphonate (4) in three steps in 39% overall yield. Starting from diethyl 3-oxobutanephosphonate (10) and diphenyl(3-oxobutyl)phosphine oxide (13), methylenomycin B has been obtained in 34% and 27% overall yield, respectively. A characteristic feature of these syntheses of methylenomycin B is that the exo-methylene function is introduced via the Horner-Wittig reaction of formaldehyde (36% aqueous solution) with the corresponding alpha-phosphorylcyclopentenones 6 and 20. The latter were obtained from phosphorylated 1,4-diketones by intramolecular base-catalyzed cyclization. A brief discussion of some mechanistic aspects of the Conant reaction is also given.
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页码:1217 / 1223
页数:7
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