New Pathway to C2-Symmetric Atropoisomeric Bipyridine N,N′-Dioxides and Solvent Effect in Enantioselective Allylation of Aldehydes
2008
Abstract
The [2+2+2] cyclotrimerization of 1,7,9,15-hexadecatetrayne with nitriles catalyzed by dicarbonylcyclopentadienylcobalt(I) opened a new pathway for the synthesis of C2-symmetrical bis(tetrahydroisoquinolines) that were used as starting material for the preparation of axially chiral bipyridine N,N'-dioxides. A dramatic solvent effect was observed where the use of different solvents induced opposite chiralities of the product with the same enantiomer of the catalyst.