Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines
Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines
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DOI：
10.1002/anie.201709224
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发表时间：
2017-11-27
影响因子：
16.6
通讯作者：
Enders, Dieter
中科院分区：
文献类型：
--
作者：
Kaya, Ugur;Chauhan, Pankaj;Enders, Dieter
利用吡唑啉-5-酮衍生的N- boc酮胺与2-萘酚进行了史无前例的多米诺- aza-Friedel-Crafts/N， o -乙酰化反应。该新方法只需要0.5mol%的双功能方酰胺催化剂负载，可扩展到克量，并提供了一系列具有两个相邻四取代立体中心的呋喃萘唑烷酮衍生物，其收率（95-98%）和立体选择性（bbb99:1 dr和97-98% ee）优异。在1-萘酚和其他富电子酚的情况下，观察到不同的反应活性，导致aza-Friedel-Crafts加合物的产率为70-98%，ee为47-98%。
N-Boc ketimines derived from pyrazolin-5-ones were explored to develop an unprecedented domino aza-Friedel-Crafts/N,O-acetalization reaction with 2-naphthols. The novel method requires a catalyst loading of only 0.5mol% of a bifunctional squaramide catalyst, is scalable to gram amounts, and provides a new series of furanonaphthopyrazolidinone derivatives bearing two vicinal tetra-substituted stereogenic centers in excellent yields (95-98%) and stereoselectivity (>99:1 d.r. and 97-98% ee). A different reactivity was observed in the case of 1-naphthols and other electron-rich phenols, which led to the aza-Friedel-Crafts adducts in 70-98% yield and 47-98% ee.