01239nas a2200181   4500008004100000022001400041245008700055210006900142260010600211300001400317490000700331520052600338100002100864700001700885700002600902700002200928856010700950       2012                        eng d  a0957-416600aAsymmetric synthesis of (+)-stagonolide C and (-)-aspinolide A via organocatalysis0 aAsymmetric synthesis of stagonolide C and aspinolide A via organ  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcDEC  a1534-15410 v233 a<p>A new enantioselective synthesis of two important fungal metabolites, (+)-stagonolide C and (-)-aspinolide A, has been described from readily available raw materials. Praline catalyzed asymmetric alpha-aminooxylation and Jorgensen's epoxidation of aldehydes are the key reactions employed in the introduction of chirality. The formation of the 10-membered lactone core structure was finally accomplished via Steglich esterification and ring closing metathesis reactions. (C) 2012 Elsevier Ltd. All rights reserved.</p>1 aShelke, Anil, M.1 aRawat, Varun1 aSuryavanshi, Gurunath1 aSudalai, Arumugam  uhttps://library.ncl.res.in/content/asymmetric-synthesis-stagonolide-c-and-aspinolide-organocatalysis-001695nas a2200181   4500008004100000022001400041245015200055210006900207260000800276300001400284490000700298520098500305100002101290700002301311700002301334700002601357856013001383       2022                        eng d  a0022-326300aAcetic acid-catalyzed regioselective C(sp(2))-H bond functionalization of indolizines: concomitant involvement of synthetic and theoretical studies0 aAcetic acidcatalyzed regioselective Csp2H bond functionalization  cAPR  a5097-51120 v873 a<p>
	An atom economical and environmentally benign protocol has been developed for the regioselective C(sp2)-H bondfunctionalization of indolizines. The acetic acid-catalyzed cross-coupling reaction proceeds under metal-free conditions, producing awide range of synthetically useful indolizine derivatives. The present protocol showed good functional group tolerance and broadsubstrate scope in good to excellent yields. Quantum mechanical investigation using density functional theory (DFT) has played acrucial role in understanding that acetic acid is the key player in determining the actual pathway as the catalyst and its ultrafastnature. Different pathways involving inter- and intramolecular proton transfer, with or without acetic acid, were investigated.Calculated results revealed that a proton shuttle mechanism is involved for the least energetic, most favorable acetic acid-catalyzedpathway. Furthermore, regioselectivity has also been explained theoretically.</p>
1 aMane, Kishor, D.1 aMukherjee, Anirban1 aDas, Gourab, Kanti1 aSuryavanshi, Gurunath  uhttps://library.ncl.res.in/content/acetic-acid-catalyzed-regioselective-csp2-h-bond-functionalization-indolizines-concomitant