Preparation of Enantiopure 1-Azabicyclo[3.2.2]nonanes Functionalized at Carbon C3, from Cinchonine and Cinchonidine. Stereoselective Solvolysis and an Easily Enolizable Ketone
摘要:
Solvolysis of C9 mesylated cinchonidine 1-OMs and cinchonine 2-OMs in solvent MeOH, EtOH, and CF3CH2OH affords ring-expanded 1-azabicyclo[3.2.2]nonanes oxygenated at carbon C3 ("second Cinchona rearrangement"). The newly introduced substituents at C3 and the neighboring quinolyl group Q' at C2 adopt quasiequatorial positions. The derived 1-azabicyclo[3.2.2]nonan-3-ones 5 and 6 are easily equilibrated. On contact with MeOD uptake of deuterium takes place at room temperature.
Preparation of Enantiopure 1-Azabicyclo[3.2.2]nonanes Functionalized at Carbon C3, from Cinchonine and Cinchonidine. Stereoselective Solvolysis and an Easily Enolizable Ketone
作者:Stefanie Röper、M. Heiko Franz、Rudolf Wartchow、H. Martin R. Hoffmann
DOI:10.1021/jo026890d
日期:2003.6.1
Solvolysis of C9 mesylated cinchonidine 1-OMs and cinchonine 2-OMs in solvent MeOH, EtOH, and CF3CH2OH affords ring-expanded 1-azabicyclo[3.2.2]nonanes oxygenated at carbon C3 ("second Cinchona rearrangement"). The newly introduced substituents at C3 and the neighboring quinolyl group Q' at C2 adopt quasiequatorial positions. The derived 1-azabicyclo[3.2.2]nonan-3-ones 5 and 6 are easily equilibrated. On contact with MeOD uptake of deuterium takes place at room temperature.
The First and Second <i>Cinchona</i> Rearrangement. Two Fundamental Transformations of Alkaloid Chemistry
作者:M. Heiko Franz、Stefanie Röper、Rudolf Wartchow、H. M. R. Hoffmann
DOI:10.1021/jo030363s
日期:2004.4.1
Stereochemistry, products, and driving forces of the “first and second Cinchona rearrangement” have been investigated and a unified theory is presented. The first cage expansion affords [3.2.2]azabicyclic α-amino ether and is formulated via a configurationally stable bridgehead iminium ion and quasiequatorial nucleophilic attack. The second cage expansion affords β-functionalized [3.2.2]azabicycles