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
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
A synthesis of multisubstituted vinylsilanes via ynolates: stereoselective formation of β-silyl-β-lactones followed by decarboxylation
作者:Mitsuru Shindo、Kenji Matsumoto、Kozo Shishido
DOI:10.1039/b418310j
日期:——
(Z)-Selective synthesis of multisubstituted vinylsilanes was achieved by stereoselective protonation or alkylation of beta-silyl-beta-lactone enolates, prepared by cycloadditions of acylsilanes with ynolates, followed by decarboxylation.
Asymmetric inverse electron-demand 1,3-dipolar cycloaddition of ynolates with chiral nitrones produced 5-isoxazolidinones with good diastereoselectivity. These products were easily converted into optically pure β-amino acids and chiral γ-butyrolactones.