Reactions of the Bornyl and Fenchyl Grignard Reagent with Chlorophosphanes â Diastereoselectivity and Mechanistic Implications
作者:Jens Beckmann、Alexandra Schütrumpf
DOI:10.1002/ejoc.200900908
日期:2010.1
The reactions of the bornyl and fenchyl Grignard reagent with the chlorophosphanes Ph 2 PCl, PCl 3 and (Et 2 N) 2 PCl, respectively, were studied by multinuclear NMR spectroscopy. The diastereoselectivity was found to be independent of the diastereomeric composition of the bornyl and fenchyl Grignard reagent (e.g., the endo/exo ratio), but dependent on the chlorophosphanes used. The results are consistent
冰片基和芬基格氏试剂分别与氯膦 Ph 2 PCl、PCl 3 和 (Et 2 N) 2 PCl 的反应通过多核 NMR 光谱进行了研究。发现非对映选择性与冰片基和芬基格氏试剂的非对映体组成(例如,内/外比)无关,但取决于所使用的氯膦。结果与涉及 SET 过程和自由基中间体的反应机制一致。对于涉及Ph 2 PCl 和PCl 3 的反应,没有观察到或几乎没有非对映选择性。冰片基和芬基格氏试剂与 (Et 2 N) 2 PCl 的反应提供了具有高非对映选择性(92% 和 88% de )。新型手性氧化膦冰片基Ph 2 PO (2a)、异冰片基Ph 2 PO (2b)、α-fenchylPh 2 PO (8a) 和 β-fenchylPh 2 PO (8b)、次膦酸冰片基 P(O)(H)-(OH) (5a) 和 β-fenylP(O)(H)(OH) (11b)和膦酸冰片基P(O)(OH) 2 (6a)和β-芬基P(O)(OH)