01661nas a2200157   4500008004100000022001400041245017500055210006900230260007100299300001400370490000700384520094400391100002401335700001901359856012501378       2014                        eng d  a0022-326300aBase-stimulated 1,2-, 1,4-, and 1,6-eliminations in suitably substituted alkylidenesuccinates leading to natural and unnatural conjugated alkenyl(methyl)maleic anhydrides0 aBasestimulated 12 14 and 16eliminations in suitably substituted   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a2538-25460 v793 a<p>With dimethyl maleate as the starting material, facile stereoselective syntheses of natural and unnatural conjugated alkenyl(methyl)maleic anhydrides have been described. The key reactions were base-endorsed novel 1,2-, 1,4-, and 1,6-eliminations in the corresponding alkylidenesuccinate derivatives. The 1,2-eliminations in cyclic carbonate and sulfite by regioselective abstraction of methine protons with the respective release of CO2 and SO2 provided a conjugated ketone product. The characteristic 1,4- and 1,6-elimination reactions with respective release of acetone and mesylate furnished the corresponding unsaturated alcohols. The obtained allylic alcohols were transformed into conjugated alkenyl(methyl)maleic anhydrides via oxidation followed by a Horner-Wadsworth-Emmons reaction pathway in very good yields. The mechanistic aspects involved in these significant elimination reactions have also been described in brief.</p>1 aDeore, Prashant, S.1 aArgade, N., P.  uhttps://library.ncl.res.in/content/base-stimulated-12-14-and-16-eliminations-suitably-substituted-alkylidenesuccinates-0