Zhang Fanglin, Peng Yiyuan, Gong Yuefa
Department of Chemistry, Huazhong University of Science and Technology, Hubei, China.
Chirality. 2008 Jun;20(6):805-11. doi: 10.1002/chir.20549.
A highly enantioselective approach for preparing optically active bicyclic piperidines is described. The key step for introducing chiral centers was a L-proline catalyzed direct enantioselective aldol reaction of 3-phthalimidopropanal with aliphatic ketones. In the reactions with alicyclic ketones, a highly enantioselective formation of anti-2-(3-phthalimido-1-hydroxypropyl)cycloketones 1a-1b (>99% ee) was observed. The aldol products 1 could be subsequently converted into bicyclic piperidines 2 via a consecutive reductive deprotection, acylation, ring closure, and hydrolysis.
描述了一种制备光学活性双环哌啶的高度对映选择性方法。引入手性中心的关键步骤是L-脯氨酸催化的3-邻苯二甲酰亚胺基丙醛与脂肪族酮的直接对映选择性羟醛缩合反应。在与脂环族酮的反应中，观察到反式-2-(3-邻苯二甲酰亚胺基-1-羟丙基)环酮1a-1b的高度对映选择性形成(对映体过量>99%)。羟醛缩合产物1随后可通过连续的还原脱保护、酰化、环化和水解反应转化为双环哌啶2。
