Enantioselective Diels–Alder Reaction of α-Acyloxyacroleins Catalyzed by Chiral 1,1′-Binaphthyl-2,2′-diammonium Salts
作者:Akira Sakakura、Kenji Suzuki、Kazuaki Ishihara
DOI:10.1002/adsc.200600322
日期:2006.11
activity and enantioselectivity for the Diels–Alder reaction of α-acyloxyacroleins. For example, in the presence of 5 mol % of 2a and 9.5 mol % of Tf2NH, the Diels–Alder reaction of α-(cyclohexanecarbonyloxy)acrolein with cyclopentadiene proceeded in EtCN at −75 °C to give the adducts in 88 % yield with 92 % exo and 91 % ee. The electron-donating property of the acyl group of the α-acyloxyacroleins increases
手性1,1'-联萘-2,2'-二胺(2a)和三氟甲磺酰亚胺(Tf 2 NH)的二铵盐对α-酰氧基丙烯醛的Diels-Alder反应显示出优异的催化活性和对映选择性。例如,在5 mol%的2a和9.5 mol%的Tf 2 NH存在下,α-(环己烷羰氧基)丙烯醛与环戊二烯的Diels-Alder反应在-75°C的EtCN中进行,得到88%的加合物。产率为92%的exo和91%的ee。α-酰氧基丙烯醛的酰基的供电子性提高了对映选择性,这是由于在过渡状态下酰基与铵基的质子之间形成了强分子内氢键。通过将可商购的手性二胺和Tf 2 NH混合,可以容易地就地制备该催化剂。