Ribes Celia, Falomir Eva, Carda Miguel, Marco J Alberto
Departament de Química InorgAnica y OrgAnica, Universitat Jaume I, Castellón, E-12080 Castellón, Spain.
Org Lett. 2007 Jan 4;9(1):77-80. doi: 10.1021/ol062570v.
[reaction: see text] A stereocontrolled, convergent synthesis of the alkaloid australine, a glycosidase inhibitor of the pyrrolizidine class, is described. The chiral starting materials were ketone 3, derived from L-erythrulose, and alpha-alkoxy aldehyde 4, prepared from L-malic acid. A key step of the synthesis was the highly stereoselective aldol reaction between 4 and a Z boron enolate derived from 3. Another key step was the one-pot construction of the bicyclic pyrrolizidine system by means of a three-step sequence of SN2 displacements induced by benzylamine on a trimesylate precursor.
[反应：见正文] 本文描述了吡咯里西啶类糖苷酶抑制剂生物碱澳洲茄胺的立体控制收敛合成。手性起始原料是由L-赤藓糖衍生的酮3和由L-苹果酸制备的α-烷氧基醛4。该合成的关键步骤是4与由3衍生的Z-硼烯醇化物之间的高度立体选择性羟醛反应。另一个关键步骤是通过苄胺对均三甲苯磺酸盐前体诱导的三步SN2取代序列一锅构建双环吡咯里西啶体系。
