Design And Synthesis Of Novel Bisphosphine Ligands

Axial chiral compounds as ligands are widely used in asymmetric catalysis.The stability of stereoconfiguration depends mainly on the number and size of adjacent groups around the rotation axis.There are several common skeletons found in axial chiral ligands,such as binaphthyls,chiral spiro skeleton,ferrocene skeleton.Among of them,axial chiral phosphine ligands play important roles for developing various asymmetric synthetic methods to access chiral compounds.Thus,the stable and common chiral bisphosphine ligands have attracted intensive attention,but most of them was not easy to obtain and modify.Therefore,design and synthesis of easily accessible and modulated chiral bisphosphine ligands are desirable for application in asymmetric catalytic reactions.A summary of several axial chiral bisphosphine ligands with different skeletons including their synthetic methods and applications were documented.A new type of novel atropisomeric bisphosphine ligands was designed and synthesized by using commercially available(S)-Binol as starting meterial.A reasonable synthetic route was designed to access diverse biphosphine ligands with different electronic and steric properties by installing various substitution groups easily.A series of ligands were successfully obtained in medium to good yield.Finally,potential application in asymmetric catalysis was explored.Preliminary results showed good reactivity and somehow enantioselectivity in Sakurai-Hosomi allylation of simple ketones.