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 w ell as the study on the behavior of such triflates under nucleophile treatm ent is reported. Three different nucleophile reagents have been chosen for this study: aqueous ethanol (a weak hard-base nucleophile), sodium hydroxid e (a strong hard-base nucleophile) and lithium aluminum hydride (a strong s oft-base nucleophile). It is concluded that the described norbornane-derive d bridgehead triflates react chemo selectively with these nucleophiles foll owing one of three possible reaction pathways, according to the character ( strong or weak nucleophile, hard or soft base) of the reagent. For strong n ucleophiles the HSAB principle is fulfilled. (C) 2001 Elsevier Science Ltd. All rights reserved.