Samarium diiodide-mediated reductive couplings of chiral nitrones with aldehydes/ketones and acyl chlorides
作者:Shao-Feng Wu、Yuan-Ping Ruan、Xiao Zheng、Pei-Qiang Huang
DOI:10.1016/j.tet.2010.01.011
日期:2010.2
4S)-8 with aldehydes/ketones, and the l-malic acid derived nitrone (S)-6 with aliphatic acyl chlorides have been investigated, respectively. (2R,3S,4S)-1,3,4-Trihydroxyprolinol derivatives 9a–f were obtained with high C-2/C-3 trans-selectivities, and 72:28–85:15 diastereoselectivities at the carbinol center from aromatic ketones/aldehydes, while low diastereoselectivities for aliphatic aldehydes. Conditions
该SMI 2介导的和H 2 O形促进还原性交叉耦合的的反应升酒石酸衍生的硝酮(3小号,4小号) - 8与醛/酮,和升苹果酸衍生的硝酮(小号) -已经分别研究了具有脂族酰氯的6。(2 R,3 S,4 S)-1,3,4-三羟基脯氨醇衍生物9a – f通过高C-2 / C-3反式获得-选择性和甲醇中心的芳烃酮/醛的非对映选择性为72:28-85:15,而脂族醛的非对映选择性较低。通过相应的N-羟基脯氨醇衍生物9b - f的N-O键裂解,或更方便地通过以下步骤,已经确定了合成(2 R,3 S,4 S)-3,4-二羟基脯氨醇衍生物(如18)的条件。一锅还原性的硝酮8和原位N-O键裂解所得的偶联产物。2-酰基-3-苄氧基-1-羟基吡咯烷10a – f形成的产率为48-82%,非对映选择性为74:26-78:22。揭示了反应所需的水量取决于底物。