Stereoselective dioxirane hydroxylations and the synthesis of tripod boronic acid esters

Methyl(trifluoromethyl)dioxirane (TFDO, 1b) was employed to obtain triol 7 upon direct stereoselective hydroxylation of cis,cis-1,3,5-tri-methylcyclohexane. Starting with 7, the cage-shaped 'tripod' borate ester 8 was easily obtained; 7 also provided easy access to 10, a new kind of arylboronic Brönsted-assisted Lewis acids (BLA).