Synthesis of Chiral Pyrazolone and Spiropyrazolone Derivatives through Squaramide-Catalyzed Reaction of Pyrazolin-5-ones with o-Quinone Methides

Org Lett. 2018 Feb 16;20(4):1158-1161. doi: 10.1021/acs.orglett.8b00025. Epub 2018 Feb 8.

Abstract

A bifunctional squaramide-catalyzed reaction of pyrazolin-5-ones with o-quinone methides in situ generated from 2-(1-tosylalkyl)phenols has been successfully developed, providing a facile access to chiral pyrazolones with high enantioselectivities. In addition, the chiral spiropyrazolones with adjacent tertiary and quaternary stereogenic centers can also be obtained through cascade chlorination/cyclization of the chiral pyrazolones.

Publication types

  • Research Support, Non-U.S. Gov't