Enantioselective La<sup>III</sup>-pyBOX-Catalyzed Nitro-Michael Addition to (<i>E</i>)-2-Azachalcones
作者:Gonzalo Blay、Celia Incerti、M. Carmen Muñoz、José R. Pedro
DOI:10.1002/ejoc.201201579
日期:2013.3
[La(OTf)3] complex with a new pyBOX ligand bearing a bulky 1-naphthylmethyl substituent at the 4′-position of the oxazoline ring catalyzes the conjugate addition of nitroalkanes to a broad range of (E)-2-azachalcones, providing the expected nitro-Michael products with good yields and enantiomeric excesses up to 87 %. The optical purity of the products can be increased by a single crystallization. A plausible
[La(OTf)3] 复合物与新的 pyBOX 配体在恶唑啉环的 4'-位带有庞大的 1-萘甲基取代基,催化硝基烷烃与广泛范围的 (E)-2-氮杂查耳酮共轭加成,提供预期的硝基迈克尔产品,产率良好,对映体过量高达 87%。通过单次结晶可以提高产品的光学纯度。已经提出了一个合理的立体化学模型来解释观察到的立体化学。