Asymmetric α-Hydroxylation of a Lactone with Vinylogous Pyridone by Using a Guanidine-Urea Bifunctional Organocatalyst: Catalytic Enantioselective Synthesis of a Key Intermediate for (20<i>S</i>)-Camptothecin Analogues
作者:Tatsuya Watanabe、Minami Odagi、Kota Furukori、Kazuo Nagasawa
DOI:10.1002/chem.201303633
日期:2014.1.7
We have developed a catalytic asymmetric synthesis of (S)‐4‐ethyl‐6,6‐(ethylenedioxy)‐7,8‐dihydro‐4‐hydroxy‐1H‐pyrano[3,4‐f]indolizine‐3,10(4H)dione (5 a), a synthetic intermediate for (20S)‐camptothecin analogues. A key step in this synthesis is an asymmetric α‐hydroxylation of a lactone with a vinylogous pyridone structure (8 a) by using a guanidine–urea bifunctional organocatalyst. The present oxidation
我们开发了(S)-4-乙基-6,6-(乙二氧基)-7,8-二氢-4-羟基-1 H-吡喃[3,4- f ]吲哚嗪-3,10的催化不对称合成(4 H)二酮(5 a),是(20 S)-喜树碱类似物的合成中间体。该合成的关键步骤是使用胍-脲双功能有机催化剂使具有乙烯基吡啶酮结构(8 a)的内酯不对称α-羟基化。本发明的氧化成功地应用于(+)的C20修饰的衍生物的合成- C20-desethylbenzylcamptothecin(13)。