Asymmetric Synthesis of 1,2-Diamino-4,5-dimethylcyclohexanes by Zirconium-Catalyzed and -Promoted Reductive Cyclization Reactions
作者:Fabrizia Grepioni、Stefano Grilli、Gianluca Martelli、Diego Savoia
DOI:10.1021/jo9900735
日期:1999.5.1
The asymmetric synthesis of 1,2-diamino-4,5-dimethylcyclohexanes was achieved by the zirconium-catalyzed and -promoted reductive cyclization of N,N'-di[(S)-1-phenylethyl]-4(R),5(R)-diamino-1,7-octadiene. The reaction of the diene with 5 equiv of butylmagnesium chloride and 0.1 mol % of bis(cyclopentadienyl)zirconium dichloride in diethyl ether at 0-20 degrees C gave mainly the 1(R),2(R)-diamino-4(S)
N,N'-二[(S)-1-苯基乙基] -4(R),5的锆催化和促进的还原环化反应实现了1,2-二氨基-4,5-二甲基环己烷的不对称合成(R)-二氨基-1,7-辛二烯。二烯与5当量的丁基氯化镁和0.1 mol%的双(环戊二烯基)二氯化锆在乙醚中在0-20℃下反应,主要得到1(R),2(R)-二氨基-4(S) ,具有C(2)对称性的,5(S)-二甲基环己烷衍生物,但是与四当量的二丁基锆茂茂在-78至-50℃的四氢呋喃中反应,得到的非对映异构体主要为4(R),5(S)构型。通过辅助剂的还原裂解,然后进行磺酰化反应,制备了1(R),2(R)-二(4-甲苯磺酰基)氨基)-4(S),5(S)-二甲基环己烷。