01334nas a2200157   4500008004100000022001400041245013800055210006900193260007100262300001400333490000700347520066100354100002401015700001901039856011801058       2013                        eng d  a1523-706000aReactivity umpolung in intramolecular ring closure of 3,4-disubstituted butenolides: diastereoselective total synthesis of paeonilide0 aReactivity umpolung in intramolecular ring closure of 34disubsti  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV  a5826-58290 v153 a<p>Remarkable reactivity reversal stratagem in 3,4-disubstituted butenolides under acidic conditions is described. Design of a suitably substituted multifunctional butenolide followed by an acid-catalyzed chemo- and diastereoselective intramolecular ring closure via the reactivity umpolung has been demonstrated to accomplish a concise total synthesis of paeonilide. Overall, the present protocol involves one-pot reduction of an a,alpha,beta-unsaturated carbon carbon double bond and intramolecular nucleophilic insertion of oxygen function at the electron-rich gamma-position of butenolide. The involved mechanistic aspects have also been discussed.</p>1 aDeore, Prashant, S.1 aArgade, N., P.  uhttps://library.ncl.res.in/content/reactivity-umpolung-intramolecular-ring-closure-34-disubstituted-butenolides-0