The mechanism of the Paal–Knorr furan synthesis was elucidated in 1995 by V. Amarnath et al. Amarnath's work showed that the diastereomers of 3,4-disubstituted-2,5-hexane diones react at different rates. In the commonly accepted mechanism, these diones would go through a common enol intermediate, meaning that the meso and d,l-racemic isomers would cyclize at the same rate as they form from a common intermediate.
In 1995, V. Amarnath et al. elucidated the mechanism of the Paal–Knorr furan synthesis. Their work revealed that diastereomers of 3,4-disubstituted-2,5-hexane diones react at different rates. The commonly accepted mechanism suggests these diones form a common enol intermediate, leading to the same cyclization rate for both meso and d,l-racemic isomers.