The stereoselective addition of titanium(IV) enolates of 1,3-oxazolidin-2-one and 1,3-thiazolidine-2-thione to cyclic N-acyliminium ion. The total synthesis of (+)-isoretronecanol
作者:Elaine Pereira、Conceição de Fátima Alves、Maria Alice Böckelmann、Ronaldo A. Pilli
DOI:10.1016/j.tetlet.2005.02.045
日期:2005.4
(+)-Isoretronecanol (1) has been prepared in four steps and 36% overall yield via the diastereoselective addition of the titanium(IV) enolate derived from N-4-chlorobutyryl-1,3-thiazolidine-2-thione (3) to N-Boc-2-methoxypyrrolidine (5), which afforded 2-substituted pyrrolidine 7 in 84% yield (8:1 diastereoisomeric ratio), followed by reductive recovery of the chiral auxiliary and cyclization. (c) 2005 Elsevier Ltd. All rights reserved.
(+)-异甘草次醇 (1) 通过四步反应和 36% 的总产率制备。具体而言,通过来自 N-4-氯丁酰基-1,3-恶二唑烷-2-硫酮 (3) 的钛(IV) 烯醇盐与 N-Boc-2-甲氧基吡咯烷 (5) 的对映选择性加成,获得 2-取代的吡咯烷 7,产率为 84%(对映异构比为 8:1)。随后通过还原回收手性辅助剂并进行环化。
© 2005 Elsevier Ltd. 保留所有权利。