在MgI(2) 介导的甲cyclopropyl amides和imides的环扩张中具有不同的选择性
1Davenport Research Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6. mlautens@chem.utoronto.ca
这项研究引入了一种新方法,用于利用甲基烯cyclopropanes (MCPs) 和化物合成五和六个成员的异环化合物. 这种方法提供了对环尺寸和功能化的优良控制,使各种化学合成成为可能.
科学领域:
- 有机化学 有机化学
- 异环化学 异环化学
- 合成方法论 合成方法论
背景情况:
- 甲cyclopropanes (MCPs) 是有机合成中的多功能构建块.
- 环膨胀反应为复杂的异环结构提供了有效的途径.
- 控制循环反应中的区域选择性仍然是一个关键的挑战.
研究的目的:
- 开发一种新的方法来制备五和六个成员的异环化合物.
- 为了研究单活性MCPs与阿尔迪明和阿尔代的环扩张.
- 探索影响异环环形成中分离选择性的因素.
主要方法:
- 使用单活性甲cyclopropanes (MCPs) 作为同类迈克尔受体.
- 采用化 (MgI(2)) 作为催化剂,产生双功能乙烯基酸盐.
- 与各种 aldimines 和 aldehydes 反应MCP,以诱导环膨胀和循环.
主要成果:
- 实现了具有高选择性的五和六个成员异环的分离合成.
- 证明了MCP的碳基部分决定了反应部位和环形大小.
- 观察到α-化/5-exo-tet循环与NPh(2) 和gamma-alkylation/6-exo-trig循环与2-oxazolidone.
- 报告了第一例玛-化添加物形成的案例,在一个vinylogous imide enolate和一个carbonyl化合物之间.
结论:
- 开发的方法为各种异环化合物提供了一种强大而有选择的途径.
- 反应机制受到基质的电子和硬质性质的影响.
- 这项工作扩大了MCP在异环化学中的合成实用性.
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