<i>C</i><sub>2</sub>-Symmetric 4,4′,5,5′-Tetrahydrobi(oxazoles) and 4,4′,5,5′-Tetrahydro-2,2′-methylenebis[oxazoles] as Chiral Ligands for Enantioselective Catalysis Preliminary Communication
作者:Dieter Müller、Gisela Umbricht、Beat Weber、Andreas Pfaltz
DOI:10.1002/hlca.19910740123
日期:1991.1.30
The synthesis of a series of enantiomerically pure, C2-symmetric 4,4′,5,5′-tetrahydro-2,2′-methylenebis[oxazoles] and 4,4′,5,5′-tetrahydro-2,2′-bi(oxazoles) is reported. Copper complexes with anionic tetrahydromethylenebis[oxazole] ligands are efficient catalysts for the enantioselective cyclopropane formation from olefins and diazo compounds (up to 96% ee in the reaction of styrene with menthyl diazoacetate)
一系列对映体纯的C 2对称的4,4',5,5'-四氢-2,2'-亚甲基双[恶唑]和4,4',5,5'-四氢-2,2的合成报道了′-联(恶唑)。具有阴离子四氢亚甲基双[恶唑]配体的铜络合物是有效的催化剂,用于从烯烃和重氮化合物(在苯乙烯与重氮乙酸薄荷酯的反应中,至多96%ee)形成对映选择性环丙烷。发现四氢二(恶唑)铱(I)配合物催化i-PrOH(最高91%ee)转移芳基烷基酮的加氢反应。四氢联(恶唑)钯配合物可用作烯丙基亲核取代的对映选择性催化剂(在PhCHCHCH(OAc)Ph与NaHC(COOMe)2的反应中,ee高达77%)。