用于不对称催化剂的酸捐赠剂的易斯酸增强
Steven M Banik1, Anna Levina1, Alan M Hyde1
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Science (New York, N.Y.)
|November 11, 2017
概括
化方胺通过与化三酸盐形成易斯酸复合物来激活不反应的电. 这使得通过新键催化能够对有价值的化合物进行反选择性合成.
科学领域:
- 有机化学
- 催化剂
- 不对称的合成
背景情况:
- 小分子双键 (H键) 供体,如尿素和方胺,已被确定为反选择性反应的催化剂.
- 这些催化剂通常需要高度反应的电友基质,因为它们的酸度较低.
研究的目的:
- 引入一种新型的催化模式,使用性H键捐赠者来进行具有较低反应性电友的酶选择性反应.
- 在激活具有挑战性的基质时, 证明了基质胺的有效性.
主要方法:
- 希拉尔方被设计为与三酸盐相互作用,特别结合三酸盐对子离子.
- 研究了一种稳定的易斯酸复合物,该复合物存在于squaramide和silyl triflate之间.
- 在低温下与生成的酸- 酸复合物发生反应.
- 对产生的氧碳中间体的核性添加物进行了研究,以评估其抗选择性.
主要成果:
- 化方形成稳定的易斯酸复合物与化三酸.
- 这种复合物有效地在低温下从乙烯基基底生成氧化碳中间体.
- 通过四胺和中间体之间的非共价相互作用,通过核添加物实现了对抗选择性控制.
结论:
- 一种新型的催化策略采用了奇拉 squaramides 和 silyl triflates,使以前不反应的电友能够产生反选择性反应.
- 这种方法扩大了键催化作用的范围,允许合成复杂的性分子.
- 该机制涉及通过非对应相互作用形成易斯酸复合物和精确控制立体化学.
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