Chemoselective reaction of spiro[oxirane-2,2′-norborn]-1′-yl triflates with nucleophiles: a new case of HSAB-principle dependence

The preparation of two new spiro[oxirane-2,2′-norborn]-1′-yl triflates as well as the study on the behavior of such triflates under nucleophile treatment is reported. Three different nucleophile reagents have been chosen for this study: aqueous ethanol (a weak hard-base nucleophile), sodium hydroxide (a strong hard-base nucleophile) and lithium aluminum hydride (a strong soft-base nucleophile). It is concluded that the described norbornane-derived bridgehead triflates react chemoselectively with these nucleophiles following one of three possible reaction pathways, according to the character (strong or weak nucleophile, hard or soft base) of the reagent. For strong nucleophiles the HSAB principle is fulfilled.