Synthesis and characterization of highly conjugated, chiral bridging ligands.
This paper describes the synthesis of four chiral derivatives of the electronically highly conjugated tetra-2-pyridylpyrazine (TPPZ) bridging ligand, which are denoted (R)- and (S)-4,5- and 5,6-pineno-tetra-2-pyridylpyrazine (PTPPZ). Preparation of these ligands was undertaken through the use of commercially available, enantiomerically pure (1R)- and (1S)-alpha-pinene, which was functionalized and subsequently employed in a Krohnke pyridine synthesis involving a furan-substituted pyridinium salt to yield a chiral, furan-substituted pyridyl intermediate. Oxidative degradation and subsequent reduction of this furan led to a chiral, substituted 2-pyridylaldehyde, which underwent a pyridoin condensation followed by cyclization to produce the final PTPPZ ligands.
Sauers
Angela L
AL
Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
Ho
Douglas M
DM
Bernhard
Stefan
S
D003500:Cyclization; D008024:Ligands; D008968:Molecular Conformation; D011719:Pyrazines / Q000138:chemical synthesis*; D013237:Stereoisomerism
D008024:Ligands; D011719:Pyrazines