Related Experiment Video
Updated: May 8, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Re2O7-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles
Wantanee Sittiwong1, Michael W Richardson, Charles E Schiaffo
1Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
Abstract:
Re(VII) oxides catalyze the acetalization, monoperoxyacetalization, monothioacetalization and allylation of hemiacetals. The reactions, which take place under mild conditions and at low catalyst loadings, can be conducted using hemiacetals, the corresponding O-silyl ethers, and, in some cases, the acetal dimers. Aldehydes react under similar conditions to furnish good yields of dithioacetals. Reactions of hemiacetals with nitrogen nucleophiles are unsuccessful. 1,2-Dioxolan-3-ols (peroxyhemiacetals) undergo Re(VII)-promoted etherification but not allylation. Hydroperoxyacetals (1-alkoxyhydroperoxides) undergo selective exchange of the alkoxide group in the presence of either Re2O7 or a Brønsted acid.
Related Concept Videos
Aldehydes and Ketones with Alcohols: Hemiacetal Formation
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
The carbonyl center is activated by...
α-Alkylation of Ketones via Enolate Ions
Base-Catalyzed Aldol Addition Reaction
Preparation of Aldehydes and Ketones from Alcohols, Alkenes, and Alkynes
