Practical synthesis of 1,4-dioxane derivative of the closo-dodecaborate anion and its ring opening with acetylenic alkoxides

Practical method of synthesis of the 1,4-dioxane derivative of the closo-dodecaborate anion was developed. The cleavage of the dioxonium ring in [B12H11O(CH2CH2)(2)O](-) with acetylenic alcohols gave rise to the preparation of closo-dodecaborate derivatives with terminal acetylene group. These compounds can be introduced into click reactions with phenylazide leading to the corresponding triazoles. The structures of (Bu4N)[B12H11O(CH2CH2)(2)O] and (Bu4N)(2)[B12H11(OCH2CH2)(2)OCH2C CH]center dot 0.5HOCH(2)C CH were determined by single-crystal X-ray diffraction. (C) 2007 Elsevier B.V. All rights reserved.