我们已经在铑催化的氧杂双环烯烃的不对称开环反应中证明了卤化物效应。通过使用卤化物和质子添加剂,脂肪胺的催化剂中毒效应被逆转,允许一定量的亲核试剂以高产率和 ee 反应。其次,通过简单地将铑催化剂上的卤化物配体从氯化物变为碘化物,使用芳香胺、丙二酸酯或羧酸盐亲核试剂的反应的反应性和对映选择性得到显着提高。第三,通过应用卤化物效应和更强制的反应条件,反应性较低的氧杂二环 [2.2.1] 底物反应生成合成有用的对映体富集的环己烯醇产物。
Iridium-catalyzed asymmetric ring-openingreactions of oxabicyclic alkenes with various aliphatic and aromatic secondaryamines are reported for the first time. The reaction gave the corresponding trans-1,2-dihydronaphthalenol derivatives in good yields with moderate enantioselectivities in the presence of 2.5 mol % [Ir(COD)Cl](2) and 5 mol % bisphosphine ligand (S)-p-Tol-BINAP. The trans-configuration
As an efficient catalyst, the [Ir(COD)CI](2)/NMDPP complex has been successfully applied to promote the asymmetric ring opening reaction of oxabenzonorbornadienes with various amines, which afforded the corresponding products in good yields (72-98%) with good enantioselectivities (80-90% ee). (C) 2014 Published by Elsevier Ltd.