Studies in biomimetic alkaloid syntheses. 13. Total syntheses of racemic aspidofractine, pleiocarpine, pleiocarpinine, kopsinine, N-methylkopsanone, and kopsanone
Enantioselective Michael/aza-Michael/Cyclization Organocascade to Tetracyclic Spiroindolines: Concise Total Synthesis of Kopsinine and Aspidofractine
作者:Xiaoyu Wu、Jianbiao Huang、Beibei Guo、Long Zhao、Yong Liu、Jie Chen、Weiguo Cao
DOI:10.1002/adsc.201400363
日期:2014.11.3
AbstractKopsinine and related alkaloids are attractive synthetic targets because of their structural complexity and biological activities. An organocatalytic Michael addition/aza‐Michael addition/cyclization cascade sequence has been developed for the enantioselective preparation of tetracyclic spiroindolines from 2,3‐disubstituted indoles and propargyl aldehyde in moderate to good yields and good to excellent enantioselectivities. The synthetic value of these advanced structures has been demonstrated by the synthesis of kopsinine and related alkaloids. Key steps for the concise synthesis of these alkaloids included an efficient enantioselective construction of tetracyclic spiroindolines bearing a dienamino ester moiety and the organocatalyzed nucleophilic addition of a dienamino ester to acrolein.magnified image
OGAWA, MASASHI;KITAGAWA, YOSHINORI;NATSUME, MITSUTAKA, TETRAHEDRON LETT., 29,(1987) N 34, 3985-3986
Studies in biomimetic alkaloid syntheses. 13. Total syntheses of racemic aspidofractine, pleiocarpine, pleiocarpinine, kopsinine, N-methylkopsanone, and kopsanone