CHIRAL DIPHOSPHOLES .3. IMPROVED SYNTHESIS AND COORDINATION CHEMISTRY OF (R,R)-DIPPOP

An improved, 90% yield synthesis of the chiral diphosphole, (R,R)-DIPPOP (1) is reported. The reactions of 1 with nickel, palladium, platinum and rhodium complexes are examined. 1 does not react with NiCl2. With PdCl2 and PtCl2, it forms various cis and trans diphosphine-bridged cyclooligomers of undetermined ring size. The rhodium complexes [Rh(cod)(2)]BF4, [Rh(acac)(cod)] and {Rh(mu-Cl)(cod)}(2) are good precursors for the synthesis of [Rh(cod){(R,R)-DIPPOP}]BF4, (8), [Rh(acac){(R,R)-DIPPOP}], (9), and {Rh(cod)Cl}(2){mu-P,P'-(R,R)-DIPPOP}, (10), which are fully characterized by multinuclear NMR spectroscopy.