Two new chiral phosphine ligands,1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinoxy)-L-iditol and 1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinsulphur)-L-iditol were prepared from D-mannitol.Pall...Two new chiral phosphine ligands,1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinoxy)-L-iditol and 1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinsulphur)-L-iditol were prepared from D-mannitol.Palladium catalytic systems formed with these ligands in situ were used as asymmetric homogenous catalysts for hydroesterification of styrene,giving(R)-2-phenyl propionate in 16.9 and 9.2% ee values,respectively.展开更多
The proton dissociation constants of some novel water soluble phosphine ligands containing phosphonic acid were determined pH metrically at 25℃ and at an inonic strength of 0.1mol·L -1 (KNO 3).From these data it...The proton dissociation constants of some novel water soluble phosphine ligands containing phosphonic acid were determined pH metrically at 25℃ and at an inonic strength of 0.1mol·L -1 (KNO 3).From these data it had been established that when the complexing group PPh 2 was introdued,the proton dissociating power of phosphonic acid significantly increased and the p K 1,p K 2 values were 1.35～1.75 log units smaller than those of the corresponding 2 aminoethylphosphonic acid analogues;while ertheric linkenge was introdued into the corresponding phosphonic acid,the proton dissociating ability of NH + 3, PO 3H - groups decreased and that of PO 3H 2 group increased respectively;However,as hydroxyethyl group was introduced,all proton dissociating power of NH + 3, PO 3H - and PO 3H 2 groups decreased.The ultraviolet properties of this type of phosphine complexes were also determinated.展开更多
文摘Two new chiral phosphine ligands,1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinoxy)-L-iditol and 1,4∶3,6-dianhydro-2,5-O-dideoxy-2,5-bis(dipheny-phosphinsulphur)-L-iditol were prepared from D-mannitol.Palladium catalytic systems formed with these ligands in situ were used as asymmetric homogenous catalysts for hydroesterification of styrene,giving(R)-2-phenyl propionate in 16.9 and 9.2% ee values,respectively.
文摘The proton dissociation constants of some novel water soluble phosphine ligands containing phosphonic acid were determined pH metrically at 25℃ and at an inonic strength of 0.1mol·L -1 (KNO 3).From these data it had been established that when the complexing group PPh 2 was introdued,the proton dissociating power of phosphonic acid significantly increased and the p K 1,p K 2 values were 1.35～1.75 log units smaller than those of the corresponding 2 aminoethylphosphonic acid analogues;while ertheric linkenge was introdued into the corresponding phosphonic acid,the proton dissociating ability of NH + 3, PO 3H - groups decreased and that of PO 3H 2 group increased respectively;However,as hydroxyethyl group was introduced,all proton dissociating power of NH + 3, PO 3H - and PO 3H 2 groups decreased.The ultraviolet properties of this type of phosphine complexes were also determinated.
