A series of novel chiral diphosphite ligands have been synthesized from（1R,2R）-trans-1,2-cyclohexanediol,（1S,2S）-trans-1,2-cyclohexanediol, racemic trans-1,2-cyclohexanediol and chlorophosphoric acid diary ester, and were successfully employed in the Cu-catalyzed asymmetric 1,4-conjugate addition of diethylzinc to cyclohexenone with up to 99% ee. It was found that ligand 1,2-bis[（R）-1,10-binaphthyl-2,2＇-diyl]phosphitecyclohexanediol 6a derived from racemic diol skeleton can show similar catalytic performance compared with ligand（1R,2R）-bis[（R）-1,1＇-binaphthyl-2,2＇-diyl]phosphitecyclohexanediol 6a＇ derived from enantiopure starting material. A significant dependence of stereoselectivity on the type of enone and the ring size of the cyclic enone was observed. Moreover, the configuration of the products was mainly determined by the configuration of the binaphthyl moieties of diphosphite ligands in the 1,4-addition of cyclic enones.
Novel catalytic systems for the Rh‐catalyzed hydroformylation of dicyclopentadiene have been developed using tris‐H8‐binaphthyl monophosphite as ligands containing different ester substituents at the 2’‐binaphthyl position(OCOMe,OCOPh,OCOAdamantyl and OCOPhCl).The catalysts exhibited high activity(S/C=4000,TON=3286)with good to excellent selectivity towards dialdehydes.Remarkably,the Rh(I)complex bearing the ligands with chlorophenyl ester substituents led to 99.9%conversion and 98.7%selectivity for dialdehydes under relatively mild conditions(6 MPa,120°C).
Five novel tropos （3R,4R）- and/or （3S,4S）-N-benzyltartarimide-derived biphenylphosphite ligands were synthesized and applied in the Cu-catalyzed asymmetric conjugate addition of diethylzinc to cyclic enones with up to 75% e.e. Compared with the reported ligand 1-N-benzylpyrrolidine-3,4-bis[（R）-1,1＇-binaphthyl-2,2＇-diyl]phosphite- L-tartaric acid, the issue that L-（＋）-tartaric acid backbone and （R）-binaphthyl showed strong matched/mismatched character was solved with these tropos ligands. It was found that the enantioselectivity was mainly controlled by the absolute configuration of N-benzyltartarimide backbone, and both enantiomers of the addition products can be obtained by simply changing the configuration of N-benzyltartarimide substituent.
