Vicinal dianions derived from diethyl alpha-aroylsuccinates were found to react with carbonyl compounds beta-regioselectively to afford alpha-aroyl-gamma-butyrolactones, which were converted into alpha-arylidene-gamma-butyrolactones by reduction with H-2/Pd-C followed by elimination employing methanesulfonyl chloride in pyridine. The method provides a general and convenient route to alpha-aroyland alpha-arylidene-gamma-butyrolactones. (C) 2003 Elsevier Ltd. All rights reserved.
Vicinal dianions of diethyl α-aroylsuccinates: preparation of functionalized-2,3-dihydrofurans and -furans, and diaxial 2,4-diaryl-3,7-dioxabicyclo[3.3.0]octanes
treatment of the adducts obtained with a catalytic amount of p-toluenesulfonic acid in refluxing toluene. cis-2,3-Dihydrofurans are used as precursors for the preparation of tetrasubstituted furans and diaxial 2,4-diaryl-3,7-dioxabicyclo[3.3.0]octanes.
(±)-Thuriferic acidethyl ester, its analogues as well as (±)-picropodophyllone have been prepared. The synthetic strategy is based on the utility of vicinal dianions derived from α-aroylsuccinic esters.