204004-82-0Relevant articles and documents
Advanced intramolecular diels-alder study toward the synthesis of (-)- morphine: Structure correction of a previously reported Diels-Alder product
Butora, Gabor,Gum, Andrew G.,Hudlicky, Tomas,Abboud, Khalil A.
, p. 275 - 278 (2007/10/03)
A tricyclic ring system 18 containing all 5 chiral centers of the natural (-)-morphine skeleton has been synthesized in 9 steps. cis-Dienediol 11 was produced by a batch microbial dihydroxylation of (2-azidoethyl)benzene with the E. coli strain JM109(pDTG601). The key step in the synthesis was a thermal [4+2] intramolecular Diels-Alder cycloaddition of triene 16 which afforded the tricyclic adduct 17 in 62% yield. After deprotection, the absolute stereochemistry of the alcohol 18 was determined by X-ray crystallographic analysis. The previously reported Diels-Alder adduct 4a was deprotected and the absolute stereochemistry of the free alcohol was assigned by X-ray crystallography to have the structure 4c. This finding therefore constitutes the correction of the structure for 4a.