Enantio- and diastereoselective construction of vicinal quaternary and tertiary carbon centers by catalytic Michael reaction of α-substituted β-keto esters to cyclic enones
作者:Keisuke Majima、Shin-ya Tosaki、Takashi Ohshima、Masakatsu Shibasaki
DOI:10.1016/j.tetlet.2005.05.139
日期:2005.8
A catalytic enantio- and diastereoselective Michael reaction was achieved to construct vicinal quaternary and tertiary carbon centers in one step. Using 5 mol % of La(O-i-Pr)3 and 10 mol % of a new N-linked-BINOL type ligand, the reaction of α-substituted β-keto esters to cyclic enones provided the corresponding Michael adducts in up to quantitative yield with a diastereomeric ratio up to 86/14 and
一步完成了一个催化的对映体和非对映体选择性迈克尔反应,从而构建了相邻的季碳和叔碳中心。使用5 mol%的La(O- i- Pr)3和10 mol%的新的N-联-BINOL型配体,α-取代的β-酮酯与环状烯酮的反应可提供相应的迈克尔加成定量收率,主要异构体的非对映异构体比率高达86/14,对映异构体过量高达86%。还研究了使用La(OTf)3代替La(Oi - Pr)3的另一种催化剂制备方法。