Asymmetric synthesis of β-amino-γ-substituted-γ-butyrolactones: double diastereoselective conjugate addition of homochiral lithium amides to homochiral α,β-unsaturated esters
作者:Thaïs Cailleau、Jason W. B. Cooke、Stephen G. Davies、Kenneth B. Ling、Alan Naylor、Rebecca L. Nicholson、Paul D. Price、Paul M. Roberts、Angela J. Russell、Andrew D. Smith、James E. Thomson
DOI:10.1039/b712937h
日期:——
Chiral alpha,beta-unsaturated esters, containing a single, gamma-stereogenic centre, show modest levels of substrate control upon conjugate addition of lithium dibenzylamide. Double diastereoselective conjugate additions of homochiral lithium N-benzyl-N-(alpha-methylbenzyl)amide to the homochiral alpha,beta-unsaturated esters display "matching" and "mismatching" effects. In each case, however, these
包含单个γ-立体异构中心的手性α,β-不饱和酯在共轭添加二苄基氨基化锂时显示适度的底物控制水平。高手性N-苄基-N-(α-甲基苄基)酰胺的双非对映选择性共轭加成到高手性α,β-不饱和酯上显示出“匹配”和“不匹配”的效果。然而,在每种情况下,这些添加都是在酰胺锂的主要立体控制下进行的,从而以高de得到相应的β-氨基酯。通过将酯官能团改变为恶唑烷酮,注意到了立体选择性的显着逆转。随后的O-脱保护和所得β-氨基加合物的环化以良好的收率和高的脱除率获得相应的β-氨基-γ-取代的γ-丁内酯。