Platinum-Catalysed Allylic Alkylation: Reactivity, Enantioselectivity, and Regioselectivity
作者:A. John Blacker、Matthew L. Clarke、Michael S. Loft、Mary F. Mahon、Mark E. Humphries、Jonathan M. J. Williams
DOI:10.1002/(sici)1521-3765(20000117)6:2<353::aid-chem353>3.0.co;2-u
日期:2000.1.17
The use of platinum complexes as catalysts for allylic substitution has been studied. A variety of different complexes catalyse the reaction, and several substrates have been tested. In the alkylation of mono(alkyl)-substituted allylic acetates, regioselectivity is highly dependent on ligand choice. By using tricyclohexylphosphine as the ligand, almost complete formation of branched products is observed
已经研究了使用铂络合物作为烯丙基取代的催化剂。多种不同的络合物催化反应,并且已经测试了几种底物。在单(烷基)取代的烯丙基乙酸酯的烷基化中,区域选择性高度依赖于配体的选择。通过使用三环己基膦作为配体,观察到几乎完全形成支链产物。还描述了利用手性二苯基膦基恶唑啉配体(缩写为(S)-PN)的高对映选择性(约80-90%ee)反应的发展。对映选择性高度依赖于配体与铂的比例(当配体/ Pt之比大于1:1时,ee急剧下降)。这与钯形成对比,并且根据两种金属的不同配位化学来解释(当与铂络合时,(S)-PN是半不稳定的),并且对于利用异双配体的未来系统具有重要意义。还描述了两种等电铂和钯配合物[[((S)-PN] MCl2]]的晶体结构。