A Simple and Efficient Synthesis of 1,4- and 1,5-Dioxepan-2-one
作者:Ali Hassannia、Graeme Piercy、Nabyl Merbouh
DOI:10.2174/157017809789124849
日期:2009.9.1
A novel synthesis of 1,4- and 1,5-dioxepan-2-one lactones was achieved through the regioselective oxidation of 3-(2-hydroxyethoxy)propan-1-ol. Under basic conditions, when 3-(2-hydroxyethoxy)propan-1-ol was oxidized using oxoammonium salts, a quantitative oxidative esterification was observed, resulting in a regioselective lactone ring closure. This oxidation was tailored to afford 1,4-dioxepan-2-one in very good yield.
Catalytic discrimination between inequivalent formyl groups was achieved using an aniline-type acid–base catalyst for the regio-, diastereo-, and enantioselective intramolecular cross-aldol reactions of enolizable dials. Although L-proline gave a mixture of the regio- and stereoisomeric products in the presence of an N-containing 1,6-dial, the aniline-type catalyst afforded anti-3,4-disubstituted pyrrolidine