Synthesis of cyclic silyl enol ethers from α-Aryl-α-diazoketones: new building blocks for preparation of indanones and α,β-unsaturated ketones

Abstract

A new strategy for in situ generation of vinyl cation intermediates from α-diazocarbonyl compounds is described in this paper. The reaction of α-aryl-α-diazoketones with trialkylsilyl triflates proceeded smoothly to produce cyclic silyl enol ethers via vinyl cation intermediates. The cyclic silyl enol ethers obtained were successfully employed as building blocks to prepare a variety of indanones and α,β-unsaturated ketones using FeCl₃ and FeCl₃·6H₂O as oxidants, respectively. The in situ generation of vinyl cation intermediates in the reaction of α-aryl-α-diazoketones with trialkylsilyl triflates was verified by control experiments and DFT calculations.