Asymmetric cyano-ethoxycarbonylation of aldehydes catalyzed by self-assembled titanium catalyst
作者:Shaohua Gou、Xiaohua Liu、Xin Zhou、Xiaoming Feng
DOI:10.1016/j.tet.2007.05.060
日期:2007.8
aromatic aldehydes, aliphatic aldehydes, and α,β-unsaturated aldehydes were found to be suitable substrates in the presence of the self-assembled titanium catalyst (5 mol % 1h, 5 mol % 2b, and 5 mol % Ti(OiPr)4). The desired cyanohydrin ethyl carbonates were afforded with high isolated yields (up to 95%) and moderate to good enantioselectivities (up to 92% ee) under mild conditions (at −15 °C). A possible
已经开发了一种基于钛配合物的新型自组装催化剂,用于醛的有效对映选择性氰基-乙氧基羰基化。自组装催化剂很容易由(R)-3,3'-双((甲基((S)-1-苯基乙基)氨基)甲基)-1,1'-联萘-2,2'-二醇(1h),N -((1S,2R)-2-羟基-1,2-二苯乙基)乙酰胺(2b)和钛酸四异丙酯(Ti(O i Pr)4)。发现在自组装钛催化剂(5 mol%1h,5 mol%2b,和5mol%的Ti(O i Pr)4)。在温和的条件下(-15℃)以较高的分离产率(最高95%)和中等至良好的对映选择性(最高92%ee)提供了所需的氰醇乙酯碳酸酯。提出了基于实验观察的可能的催化循环。