| SYNTHESIS |
An efficient route to (R)-(+)-muscopyridine, a component of natural musk, has been devised by Alois Fürstner and Andreas Leitner of Max Planck Institute for Coal Research, Mülheim an der Ruhr, Germany [Angew. Chem. Int. Ed., 42, 308 (2003)]. It begins with two iron-catalyzed couplings of alkyl groups to form the disubstituted pyridine shown at top. Coupling of the first alkyl group (red) yields the monosubstituted pyridine substrate for the second coupling, as well as a symmetrical diene by-product. During coupling with the second alkyl group (black), only the monosubstituted substrate reacts, forming an unsymmetrical diene. Ring-closing metathesis with a ruthenium-indenylidene complex converts the unsymmetrical diene, but not the symmetrical diene by-product, into a macrocyclic olefin. However, when solvent is removed, the ruthenium complex forces the by-product to polymerize without causing the cyclic olefin to reopen. When the crude mixture of cyclic olefin, polymeric by-product, and ruthenium complex is subjected to hydrogenating conditions, the cyclic olefin is reduced, with the ruthenium complex serving as precatalyst. (R)-(+)-Muscopyridine (bottom) is separated from the polymeric by-product by filtration through a short column of silica. |
| UPDATE | 01.03 |
| AUTHOR |
Max Planck Institute for Coal Research's - Fuerstner Alois - Leitner Andreas |
| LITERATURE REF. | Angew. Chem. Int. Ed., 42, p. 308 (2003) |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |