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Synthesis of the Azaoxoaporphine Alkaloid Sampangine and Ascididemin‐Type Pyridoacridines through TMPMgCl·LiCl‐Mediated Ring Closure
Author(s) -
Plodek Alois,
König Mathias,
Bracher Franz
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201403502
Subject(s) - chemistry , moiety , negishi coupling , ring (chemistry) , alkaloid , intramolecular force , stereochemistry , total synthesis , organic chemistry , catalysis
We report the synthesis of the azaoxoaporphine alkaloid sampangine ( 4 ) and a series of ring A analogues and isomers of the marine pyridoacridine alkaloid ascididemin ( 2 ). This approach starts from readily available 1‐bromo[2,7]naphthyridine ( 12 ) or 4‐bromobenzo[ c ][2,7]naphthyridine ( 5 ), and the ring A scaffold bearing an ester moiety is introduced by a Suzuki or Negishi cross‐coupling reaction. The final cyclization step was achieved through a directed remote ring metallation with the Knochel–Hauser base (TMPMgCl · LiCl; TMP = 2,2,6,6‐tetramethylpiperidinyl), followed by intramolecular trapping of the ester group.