Bicyclic and Tricyclic Compounds with β-Amino Alcohol Groups as Chiral Ligands in the Enantioselective Reaction of Diethylzinc with Aldehydes
作者:Hans Günter Aurich、Frank Biesemeier、Michael Geiger、Klaus Harms
DOI:10.1002/jlac.199719970222
日期:1997.2
X-ray analyses of compounds 11Ff, 17, and 11Af · HCl were performed. The bicyclic and tricyclic compounds were used as chiral ligands in the reaction of diethylzinc with aldehydes 19, in particular with benzaldehyde (19a). Using bicyclic compounds with a tertiary β-hydroxyalkyl substitutent at the N atom as ligands, ee's in the range of 78 to 95% were found. Whereas for the best ligands 11Ae and Af the
用DIBAH还原对映体纯的烯丙氧基酯9或ent - 9,得到相应的醛,用手性或非手性羟胺8原位处理,得到硝酮10。它们自发地进行分子内的1,3-偶极环加成,分别得到双环化合物11和12。以类似的方式,制备三环化合物14和15的混合物。用环己烯氧化物处理化合物16得到非对映异构体17和18的混合物。非对映体14和15以及17和18可以通过色谱法分离。对化合物11Ff,17和11Af ·HCl进行了X射线分析。在二乙基锌与醛19,特别是与苯甲醛(19a)的反应中,双环和三环化合物用作手性配体。使用在N原子上具有叔β-羟基烷基取代基的双环化合物作为配体,发现ee在78%至95%的范围内。而最佳配体11Ae和Af4-甲苯甲醛反应中的对映选择性仅略有降低,而脂族醛19c和d的对映选择性明显降低。