Synthesis of phthalides from bis-propargyl ethers: use of Garratt–Braverman cyclization to construct the phthalans and IBX as a new reagent for subsequent oxidation
摘要:
An efficient route to phthalides is described starting from easily available bis-propargyl ethers. The method involves Garratt-Braverman cyclization of the ethers to phthalans which are then efficiently oxidized to the phthalides by iodoxy benzoic acid (IBX) which has been shown to be a superior reagent in terms of yield and reagent stoichiometry for such a transformation in comparison with more commonly used KMnO4/CuSO4 reagent. (C) 2015 Elsevier Ltd. All rights reserved.