| 摘要 |
<p>A method for preparing a penem intermediate is provided to decrease the amount of a rhodium catalyst used significantly by using a copper catalyst as an auxiliary catalyst and produce a target product very economically by increasing the efficiency of the rhodium catalyst. A method for preparing a bicyclic keto ester compound represented by a formula(1) from a diazo compound represented by a formula(2) is characterized in that a rhodium catalyst and a copper catalyst, which is copper powder, Cu(I) compound or Cu(II) compound, are simultaneously used. In the formulae(1) and (2), R is a protecting group of a carboxylic acid which is C1-4 alkenyl, or benzyl substituted with para nitro, para C1-4 alkoxy or para C1-6 alkyl; R^1 is H, optionally substituted alkyl, optionally substituted aryl, or optionally substituted heterocyclyl; R^2 is H, acyl or silyl which is tri-substituted with alkyl and aryl, provided that the compound of the formula(1) and the compound of the formula(2) are existent in various optical isomers due to the presence of non-symmetric carbon atoms. In the formula(3), X is O or alkyl-substituted N; and each R1, R2 and R3 is H, C1-30 alkyl or fluorine substituted alkyl.</p> |
