Resolution of trans-2-azidocycloalkanols by separation of their mandelic acid esters

It is presented that resolution of (+/-)-trans-2-azidocylohexanol and (+/-)-trans-2-azidocyclooctanol can be effected with (R)-mandelic acid. (R)-Mandelate esters of these azido alcohols can be separated by column chromatog-raphy on silica gel in an efficient manner. Upon methanolysis (transesterification) of the diastereomerically pure (R)-mandelate esters by K2CO3, enantiomerically pure trans-2-azidocylohexanols and trans-2-azidocyclooctanols are obtained. Their synthetic relevance has been also demonstrated by subjecting them to some enantiospecific transformations, such as the Mitsunobu reaction and hydrogenolysis of the azide functionality. Notably, this is the first study reporting the preparation of enantiopure trans-2-azidocyclooctanols.