Enantioselective Synthesis of Indolizidine Alkaloid: A Formal Total Synthesis of (-)-Pumiliotoxin 251D
摘要:
An enantioselective formal total synthesis of (-)-pumiliotoxin 251D was achieved by employing the Sharpless kinetic resolution of the 2-furylmethanol derivative (3) and a stereoselective radical cyclisation of the thiocarbonyl-imidazolide (10) as key steps.
Enantioselective Synthesis of Indolizidine Alkaloid: A Formal Total Synthesis of (-)-Pumiliotoxin 251D
摘要:
An enantioselective formal total synthesis of (-)-pumiliotoxin 251D was achieved by employing the Sharpless kinetic resolution of the 2-furylmethanol derivative (3) and a stereoselective radical cyclisation of the thiocarbonyl-imidazolide (10) as key steps.
Preparation of Primary and Secondary Dialkylmagnesiums by a Radical I/Mg‐Exchange Reaction Using
<i>s</i>
Bu
<sub>2</sub>
Mg in Toluene
作者:Alisa S. Sunagatullina、Ferdinand H. Lutter、Paul Knochel
DOI:10.1002/anie.202116625
日期:2022.3.21
secondary dialkylmagnesium reagents were prepared in toluene by the reaction of sBu2Mg with alkyl iodides (25–40 °C, 1–4 h). Stereoconvergent I/Mg-exchanges were observed for secondary cyclohexyl iodides leading after quenching reactions to products with high enantio- and diastereoselectivity, including homo-aldol products. Mechanistic studies confirmed radical pathways for these exchanges.
伯二烷基镁试剂和仲二烷基镁试剂是通过s Bu 2 Mg 与烷基碘反应在甲苯中制备的(25–40 °C,1–4 小时)。观察到仲环己基碘的立体会聚 I/Mg 交换导致猝灭反应后产生具有高对映选择性和非对映选择性的产物,包括同羟醛产物。机制研究证实了这些交换的根本途径。