Synlett 2023; 34(06): 663-666
DOI: 10.1055/a-1938-1243
cluster
Chemical Synthesis and Catalysis in India

Organocatalytic Asymmetric Oxa-Michael–Michael Reaction of 3-Aryl-2-Nitroprop-2-Enols with Unsaturated Pyrazolones: Synthesis of Spirotetrahydropyranopyrazolones

Nimisha Bania
,
Dipankar Barman
,
This work was supported by MHRD-FAST programme (file no 22-3/2016-TS.II/TC) and DST-SERB (file no CRG/2018/001154). We also thank the Department of Biotechnology (DBT), Govt. of India (project no. BT/COE/34/SP28408/2018) for the provision of instrumental facilities.


Abstract

An organocatalytic asymmetric oxa-Michael–Michael reaction of 3-aryl-2-nitroprop-2-enols with alkylidene pyrazolones has been developed. This report describes the first use of a 3-aryl-2-nitroprop-2-enol as an O-nucleophile in enantioselective catalysis. With 10 mol% of a quinine-derived squaramide catalyst, a variety of spirotetrahydropyranopyrazolones were obtained in moderate yields, excellent diastereomeric ratios, and high to excellent enantioselectivities under mild reaction conditions.

Supporting Information



Publication History

Received: 30 May 2021

Accepted after revision: 07 September 2021

Accepted Manuscript online:
07 September 2022

Article published online:
28 September 2022

© 2021. Thieme. All rights reserved

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany