Nucleophilic Additions and Redox Reactions of Polyhydroxypyrroline <i>N</i>-Oxides on the Way to Pyrrolidine Alkaloids: Total Synthesis of Radicamine B
作者:Pedro Merino、Andrea Goti、Ignacio Delso、Tomas Tejero、Francesca Cardona
DOI:10.1055/s-2007-991059
日期:——
Nucleophilic addition of aryl Grignard reagents to (2 R,3 R,4 R)-3,4-bis(benzyloxy)-2-(benzyloxymethyl)-3,4-dihydro-2 H-pyrrole 1-oxide afford straightforwardly trihydroxylated -pyrrolidine alkaloids. Organometallic additions take place with -complete ANTI selectivity. In order to gain access to all four dia-stereomers with different configuration at C-2 and C-5, an oxidation-reduction protocol is
芳基格氏试剂与 (2 R,3 R,4 R)-3,4-双(苄氧基)-2-(苄氧基甲基)-3,4-二氢-2 H-吡咯1-氧化物的亲核加成得到直接三羟基化的-吡咯烷生物碱。有机金属添加具有完全的 ANTI 选择性。为了获得在 C-2 和 C-5 处具有不同构型的所有四种非对映异构体,开发了一种氧化还原协议。在亲核加成反应中观察到的高选择性允许仅通过两步和高化学产率制备天然雷克胺 B。