Transition-Metal-Free Synthesis of Aryl-Substituted tert-Butyl Ynol Ethers through Addition/Elimination Substitution at an sp Centre



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Nucleophilic attack of an alkoxide on an alkynyl sulfonamide leads to displacement of the sulfonamide at the sp centre and isolation of the ynol ether in good yield in a single operation (see scheme). The mechanistic pathway has been probed by the use of coordinating additives, 13C-labelling experiments and ab initio calculations, which indicated that an addition/elimination mechanism is in operation.