| 摘要 |
Process for preparing compounds of the formula Iin which R is alkyl or aryl, in each case unsubstituted or substituted, R3 is hydrogen, alkyl or aryl, in each case unsubstituted or substituted, and X=O or NH,which comprises reacting an aldehyde R-CHO with CO and a compound of the formula IIin which R2 is a group which reacts with a -CO2H group, which is formed during the reaction, with ring-closure to give compounds of the formula I,in the presence of a transition metal catalyst described.
|
