This study investigated a practical method for regiocontrolled synthesis of precursors of strained cyclohexynes and 1,2-cyclohexadienes, which is a one-pot procedure consisting of a rearrangement of silyl enol ether and subsequent formation of the enol triflates. Triethylsilyl enol ether, derived from cyclohexanone, was treated with a combination of LDA and t-BuOK in n-hexane/THF to encourage the migration of the silyl group to generate an α-silyl enolate. Subsequently, the α-silyl enolate was reacted with Comins’ reagent to yield the corresponding enol triflate. Finally, the α-silylated trisubstituted lithium enolate for the synthesis of 1,2-cyclohexadiene precursor was isomerized in the presence of a stoichiometric amount of water for one hour at room temperature to exclusively provide tetrasubstituted lithium enolate for the synthesis of cyclohexyne precursor in one pot.
Practical Synthesis of Precursors of Cyclohexyne and 1,2-Cyclohexadiene