Synthesis of Functionalized Allylic Sulfoxides and Their Use in the Construction of 2,3,4-Trisubstituted Furans via a [3 + 2] Annulation
作者:Zhenqian Fu、Mang Wang、Yuhui Ma、Qun Liu、Jun Liu
DOI:10.1021/jo801406p
日期:2008.10.3
A route to 2,3,4-trisubstituted furan derivatives based on a [3 + 2] annulation of functionalized allylic sulfoxides and aldehydes is described. In this strategy, the precursors of allylic sulfoxides 4, allylic sulfides 3, were synthesized via a thiomethylation reaction of an alpha-EWG ketene-S,S-acetal 1 (EWG: electron-withdrawing group), formaldehyde, and a thiol 2 in high to excellent yields. Allylic
描述了基于官能化的烯丙基亚砜和醛的[3 + 2]环化反应制备2,3,4-三取代的呋喃衍生物的途径。在这种策略中,烯丙基亚砜4的前体,烯丙基硫化物3是通过α-EWG乙烯酮-S,S-乙缩醛1(EWG:吸电子基团),甲醛和硫醇2的硫代甲基化反应合成的。高到优异的产量。使用间氯过氧苯甲酸作为氧化剂,通过高度区域选择性氧化3制备烯丙基亚砜4。因此,从这些容易获得的亚砜4开始,在温和的条件下,通过4与醛5的[3 + 2]环化反应,有效地构建了2-烷硫基3,4-二取代的呋喃6。用胺进一步取代6的2-烷硫基导致形成2-氨基-3,