Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Japan.
Org Lett. 2011 Jun 3;13(11):2944-7. doi: 10.1021/ol201007e. Epub 2011 May 10.
Highly enantioselective gem-chlorofluorination of active methylene compounds was carried out by using a copper(II) complex of a chiral spiro pyridyl monooxazoline ligand. This reaction yielded α-chloro-α-fluoro-β-keto esters and α-chloro-α-fluoro-β-keto phosphonates with up to 92% ee. The resulting dihalo β-keto ester was converted into various α-fluoro-α-heteroatom-substituted carbonyl compounds via nucleophilic substitution without loss of optical purity. A fully protected β-amino acid with a gem-chlorofluoromethylene function was also synthesized.
通过使用手性螺吡啶单噁唑啉配体的铜（II）配合物，实现了活泼亚甲基化合物的高对映选择性的偕二氯氟化反应。该反应以高达 92%的对映体过量值得到了 α-氯-α-氟-β-酮酯和 α-氯-α-氟-β-酮膦酸酯。所得的二卤代β-酮酯通过亲核取代反应转化为各种α-氟-α-杂原子取代的羰基化合物，而不会损失光学纯度。还合成了具有偕二氯氟亚甲基功能的完全保护的β-氨基酸。
