Reduction of dimethyl perfluoroadipate with Vitride yielded the title compounds, which were also prepared by dehydration of 1H,6H-perfluorohexane-1,1,6,6-tetrol. The configurations of the oxepanediols were assigned based on the crystal structure of the bis(tert-butyldiphenylsilyl) ether of the cis stereoisomer. Treatment with ethanolic HCl ring-opened the diols to 1H,6H-1,6-diethoxyperfluorohexane-1,6-diol, and dehydration with P4O10 gave perfluorohexanedial.