Enantioselective Synthesis of Optically Active Pyridine Derivatives and C 2 ‐Symmetric 2,2′‐Bipyridines

Optically active pyridine derivatives 2, 15, 18, 19, 21, 26 , and 27 are obtained by enantioselective reduction of the corresponding ketones 5, 7, 11–13, 24 , and 25 using the chiral borane reagent chlorodiisopinocampheylborane [(I pc ) 2 BCl]. Nickel(0)‐mediated coupling of bromopyridines 2, 15 , and 31 gives C 2 ‐symmetric 2,2′‐bipyridines ( R,R )‐ 32 , ( R,R′ )‐ 33 , and ( S,S )‐ 38 , respectively, which form metal complexes with Co II , Pd II , Cu I , and Ag I . Aryl‐substituted pyridines 26 , and 39–41 are synthesized by palladium(0)‐catalyzed cross couplings of 2 and 15 with boronic acids 42–44 .