Direct conversion of esters to aldehydes and ketones via piperazine amide under mild conditions

Aldehydes and ketones are basic, versatile intermediates used in organic synthesis. Various substituted aldehydes and ketones were directly prepared from carboxylic esters under mild conditions with excellent yields. The in situ generated aminolysis intermediate, piperazine-1,4-diylbis(phenylmethanone) amide, is readily reacted with commercial DIBALH and n-BuLi to obtain carbonyls in a one-pot reaction. The key amide intermediate was obtained in quantitative yield among the screened secondary amines. Hence, the formation of piperazine amide from the ester group, eliminated the utility of cryogenic temperatures and reduction proceeded under mild conditions. In addition, gram-scale preparation of aldehyde and ketone was reported in good yields.