Building C(sp3) Molecular Complexity on 2,2'-Bipyridine and 1,10-Phenanthroline in Rhenium Tricarbonyl Complexes.

The reactions of [Re(N-N)(CO) 3 (PMe 3 )]OTf (N-N= 2,2'-bipyridine, bipy; 1,10-phenanthroline, phen) compounds with t BuLi and with LiHBEt 3 have been explored. Addition to the N-N chelate took place with different site-selectivity depending on both chelate and nucleophile. Thus, with t BuLi, an unprecedented addition to C5 of bipy, a regiochemistry non-accessible for free bipy, was obtained, while coordinated phen underwent t BuLi addition to C2 and C4. Remarkably, when LiHBEt 3 reacted with [Re(bipy)(CO) 3 (PMe 3 )]OTf, hydride addition to the 4 and 6 positions of bipy triggered an intermolecular cyclodimerization of two dearomatized pyridyl rings. In contrast, hydride addition to the phen analog resulted on partial reduction of one pyridine ring. The resulting neutral Re(I) products showed a varied reactivity with HOTf and with MeOTf to yield cationic complexes. These strategies rendered access to Re(I) complexes containing bipy- and phen-derived chelates with several C(sp 3 ) centers.