Carbonylation of trichloroacetaldehyde (chloral) in concentrated sulfuric acid: Stereocontrolled synthesis of cis- and trans-2,5-bis(trichloromethyl)-1,3-dioxolan-4-one

Article abstract of DOI:10.1016/0040-4020(95)00516-B

Carbonylation of trichloroacetaldehyde(chiral) in concentrated sulfuric acid readily gave 2,5-bis(trichloromethyl-1,3-dioxolan-4-ones (cis and trans) and 3,3,3-trichloro-2-hydroxypropanoic acid. The cis isomer was isolated for the first time, and confirmed by X-ray structural analysis. The cis/trans ratio of dioxolanones largely depended upon the concentration of sulfuric acid. Highly diastereoselective formation of the dioxolanones was achieved with 99wt% sulfuric acid (cis:trans = 95:5) or with 90wt% sulfuric acid (0:100).