Squaric acid derivatives react with organolithium compounds at room te
mperature to afford with excellent yields after hydrolysis, symmetrica
l and unsymmetrically substituted oxygenated 1,4-diketones bearing alk
yl, aryl or heteroaryl groups at the carbonyl positions. In the case o
f aromatic or heteroaromatic ketones the enol tautomers are also obtai
ned