Synthesis and stereochemical study of new complexes of Pd and Pt with chiral dithioether ligands
作者:Montserrat Diéguez、Aurora Ruiz、Anna Maria Masdeu-Bultó、Carmen Claver
DOI:10.1039/b004403m
日期:——
New palladium(II) and platinum(II) complexes with two families of chiral dithioether ligands, (−)-1-benzyl-3,4-bis(methylsulfanyl)pyrrolidine (−)-degusMe2, (−)-1-benzyl-3,4-bis(isopropylsulfanyl)pyrrolidine (−)-degusPri2, (+)-1-benzyl-3,4-bis(phenylsulfanyl)pyrrolidine (+)-degusPh2, (−)-2,2-dimethyl-4,5-bis(methylsulfanylmethyl)-1,3-dioxolane (−)-diosMe2 and (−)-4,5-bis(isopropylsulfanylmethyl)-2,2-dimethyl-1,3-dioxolane (−)-diosPri2, have been prepared and characterised by NMR. The complexes [PdCl2(−)-degusMe2}], [PdCl2(+)-degusPh2}] and [PdCl2(−)-diosMe2}] show a mixture of two diastereomers in solution at room temperature. VT-NMR indicates that there is no interconversion between diastereomers at room temperature. Complex [Pt(cod)(−)-diosMe2}][BF4]2 is extremely fluxional and its diastereomers did not show isolated NMR resonances even at −90 °C. The complexes [PdCl2(−)-degusPri2}], [PdCl2(−)-diosPri2}] and [Pt(cod)(−)-diosPri2}][BF4]2, which contain a more hindered ligand, seem to be well suited for use in enantioselective catalysis because only one diastereomer is present.
新的钯(II)和铂(II)配合物与两个系列的手性二硫醚配体,(-)-1-苄基-3,4-双(甲硫基)吡咯烷(-)-degusMe2,(-)-1-苄基-3,4-双(异丙基硫基)吡咯烷(-)-degusPri2,(+)-1-苄基-3、(+)-degusPh2、(-)-2,2-二甲基-4,5-双(甲基硫甲基)-1,3-二氧戊环(-)-diosMe2 和 (-)-4,5-双(异丙基硫甲基)-2,2-二甲基-1,3-二氧戊环(-)-diosPri2。室温下,[PdCl2(-)-degusMe2}]、[PdCl2(+)-degusPh2}]和[PdCl2(-)-diosMe2}]复合物在溶液中显示出两种非对映异构体的混合物。VT-NMR 显示,非对映异构体之间在室温下没有相互转化。[Pt(cod)(-)-diosMe2}][BF4]2 复合物具有极强的通性,其非对映异构体即使在 -90 ℃ 下也不会显示出独立的核磁共振共振。[PdCl2(-)-degusPri2}]、[PdCl2(-)-diosPri2}]和[Pt(cod)(-)-diosPri2}][BF4]2 复合物含有更多受阻配体,由于只存在一种非对映异构体,因此似乎非常适合用于对映选择催化。