Ynolates were found to react with alpha-alkoxy-, alpha-siloxy-, and alpha-aryloxyketones at room temperature to afford tetrasubstituted olefins with high Z selectivity. Since the geometrical selectivity was determined in the ring opening of the beta-lactone enolate intermediates, the torquoselectivity was controlled by the ethereal oxygen atoms. From experimental and theoretical studies, the high Z
We developed the novel one‐pot synthetic method of substituted triptycenes by the reaction of ynolates and arynes. This four‐step process involves three cycloadditions and electrocyclic ring opening of the strained Dewar anthracene. Each of the three related but structurally distinct classes of nucleophiles (ynolate, enolate, and anthracenolate) reacts with o‐benzyne in the same predictable manner
Aliphatic α,α-dibromo esters, precursors of ynolates, were synthesized via bromination of lithium α-bromo ester enolates with 1,2-dibromotetrafluoroethane in good yields. α-Trimethylsilyl-α,α-dibromo esters were synthesized via radical bromination.
Ynolates react with ketones at room temperature to afford α,β,β-trisubstituted acrylates (tetrasubstituted olefins) with 2:1−8:1 geometrical selectivities. This can be regarded as a new olefination reaction of ketones giving tetrasubstituted olefins in good yield, even in the case of sterically hindered substrates. The reaction mechanism involves cycloaddition of ynolates with a carbonyl group and
reaction under acidic conditions to give its corresponding anthrone product. 9-Hydroxytriptycenes and unsubstituted triptycene undergo ring-opening reaction under strongly acidic conditions, such as with TfOH. An investigation of the substitution effect has revealed that the electron-donating group on the arene moiety allows the reaction to proceed in the presence of a weaker acid, such as TFA. In