title: Synthesis and characterization of highly conjugated, chiral bridging ligands.
abstract: 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.
authors.affiliation: Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Angela L
authors.initials: AL
authors.lastname: Sauers
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Ho
authors.forename: Stefan
authors.initials: S
authors.lastname: Bernhard
mesh_terms: D003500:Cyclization; D008024:Ligands; D008968:Molecular Conformation; D011719:Pyrazines / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D008024:Ligands; D011719:Pyrazines