Enantioselective Formation of Bicyclic Lactones by Rhodium-Catalyzed Intramolecular CH-insertion reactions
作者:Paul Müller、Philippe Polleux
DOI:10.1002/hlca.19940770307
日期:1994.5.11
leads to a 3:1 cis/trans mixture of bicyclic lactone 6a with an enantiomeric excess of 95–97% (cis) and 90% (trans). The conformationally rigid tert-butyl derivatives 5b and 5c afford, in the presence of the same catalyst, 6b and 6c, respectively, via insertion into the equatorial CH bonds exclusively, with ee's of ca. 95%. A remarkable degree of induction (92–95%) results in the lactone 6g upon decomposition
在手性[Rh 2 ((2 S)-mepy} 4 ]]存在的情况下,重氮基乙酸环己酯(5a)的分解导致双环内酯6a的3:1顺式/反式混合物,对映体过量为95-97 %(顺式)和90%(反式)。在相同催化剂的存在下,构象刚性的叔丁基衍生物5b和5c分别仅通过插入到赤道CH键中而得到ee,其ee分别为6b和6c 。95%。1-偶氮-2-甲基丙基重氮基乙酸酯(5g)分解后,内酯达到6g时,诱导度显着(92-95%)。由1-甲基环己醇,环戊醇和1-甲基环戊醇(5d–f)衍生的重氮乙酸酯在相似条件下提供的插入产物具有较高的非对映选择性,但对映选择性明显较低。其他催化剂效率较低。