Hyperconjugative Antiaromaticity Activates 4H-Pyrazoles as Inverse-Electron-Demand Diels-Alder Dienes

被引：20

作者：

Levandowski, Brian J. ^{[1
,2
]}

Abularrage, Nile S. ^{[1
]}

Houk, K. N. ^{[2
]}

Raines, Ronald T. ^{[1
]}

机构：

[1] MIT, Dept Chem, Cambridge, MA 02139 USA

[2] Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA

来源：

ORGANIC LETTERS | 2019年 / 21卷 / 20期

关键词：

AZO BRIDGES; CYCLOPENTADIENE; AROMATICITY; ISOPYRAZOLES; CYCLOADDITION; REACTIVITIES; AZINES;

D O I：

10.1021/acs.orglett.9b03351

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The Diels-Alder reactivity of 4,4-difluoro-3,5-diphenyl-4H-pyrazole was investigated experimentally and computationally with endo-bicyclo[6.1.0]non-4-yne. The computationally predicted rate enhancement from hyperconjugative antiaromaticity induced by fluorination of cyclopentadienes at the 5-position extends to five-membered heterocyclic dienes containing a saturated center. 4,4-Difluoro-4H-pyrazoles are new electron-deficient dienes with rapid reactivities toward strained alkynes.

引用

页码：8492 / 8495

页数：4

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