Re2O7-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles.
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.
Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
Wantanee
W
Sittiwong
Michael W
MW
Richardson
Charles E
CE
Schiaffo
Thomas J
TJ
Fisher
Patrick H
PH
Dussault
O,O-acetal; O,S-thioacetal; Re2O7; S,S-acetal; allylation; hemiacetal; peroxyacetal