01265nas a2200229 4500008004100000022001400041245019100055210006900246260000900315300001400324520040800338653001400746653001500760653001500775653001600790653002000806100002400826700001800850700002400868700001900892856012400911 2017 eng d a1434-193X00aUnified approach to fused and spirocyclic oxindoles through lewis-acid-promoted opening of spiroepoxyoxindoles with allylsilanes: application to the formal synthesis of (+/-)-physovenine0 aUnified approach to fused and spirocyclic oxindoles through lewi cMAY  a2603-26093 a

A protocol for the construction of oxindoles containing all-carbon quaternary centres in a highly regioselective manner has been developed. The reaction involves opening of spiroepoxyoxindoles with allylsilanes to give Hosomi-Sakurai-type products as well as new silicon-containing spirocyclic oxindoles. A formal synthesis of (+/-)-physovenine was accomplished in five steps using this protocol.

10aalkaloids10aAllylation10aannulation10aLewis acids10aspiro compounds1 aSharma, Brijesh, M.1 aYadav, Mahesh1 aGonnade, Rajesh, G.1 aKumar, Pradeep uhttps://library.ncl.res.in/content/unified-approach-fused-and-spirocyclic-oxindoles-through-lewis-acid-promoted-opening01321nas a2200217 4500008004100000022001400041245009100055210006900146260000800215490000700223520058800230653001400818653002500832653002600857653001600883653002100899100002400920700002400944700002400968856011100992 2023 eng d a2193-580700aRapid bioinspired N-acyliminium ion strategy for the ABC core of the stemona alkaloids0 aRapid bioinspired Nacyliminium ion strategy for the ABC core of  cSEP0 v123 a

A concise and highly diastereoselective bioinspired key cationic cyclization strategy for the asymmetric synthesis of the tricyclic core of the (-)-stemoamide, together with 8,9-bis-epi-stemoamide has been described. The key N-acyliminium ion precursors were accessed from L-tartaric acid and L-malic acid respectively. The use of ethyl acetoacetate derived bifunctional allylidenetriphenylphosphorane reagent in the early stage of the synthetic strategy is advantageous for the rapid construction of highly functionalized key pyrrolo[1,2-& alpha;]azepine frameworks.

10aalkaloids10aBiomimetic synthesis10aClaisen rearrangement10acyclization10aRegioselectivity1 aChavan, Subhash, P.1 aKalbhor, Dinesh, B.1 aGonnade, Rajesh, G. uhttps://library.ncl.res.in/content/rapid-bioinspired-n-acyliminium-ion-strategy-abc-core-stemona-alkaloids