20 Laurencinおよび関連化合物の合成研究

抄録

In a study aimed at the total synthesis of laurencin (1) and related compounds (2), we prepared 7,8-dihydro-2-ethyl-8-formyl-2H-oxocin-3(4H)-one ethylene acetal (3) and its derivative (46). 4-Ethyl-2-hydroxymethyl-3-oxaglutaraldehydes (20), prepared by ozonization of 5-ethyl-2-hydroxymethyl-2,5-dihydrofurans (9) (Chart 1), were submitted to the Robinson-Schopf condensation with methylamine and acetonedicarboxylic acid to give 9-methyl-9-aza-3-oxabicyclo[3.3.1]nonanes (21〜23) (Chart 3). These compounds were degraded via a several-step process into oxocin derivatives (38a〜38c) (Chart 5). One of these compounds (38a) was then converted into (3) and (46), important synthetic intermediate for laurencin (1).