# Squaramide-Catalyzed Asymmetric Michael Addition/Cyclization Reaction for the Synthesis of Chiral Bisspiro Barbituric Acid–Oxindole Derivatives

## TL;DR

A new method was developed to efficiently create chiral bisspiro compounds using a squaramide catalyst, achieving high yields and excellent stereoselectivity.

## Contribution

A novel squaramide-catalyzed tandem reaction for synthesizing chiral bisspiro barbituric acid–oxindole derivatives with high stereoselectivity.

## Key findings

- The reaction achieved good-to-high yields (up to 97%) with excellent stereoselectivities (up to >99% ee, >20:1 dr).
- The method was successfully applied on a gram scale, demonstrating its practicality.

## Abstract

An efficient stereoselective strategy for the synthesis of chiral bisspiro barbituric acid–oxindole derivatives was developed. The asymmetric Michael addition/cyclization tandem reaction between benzylidene barbituric acids and oxindolylmalonitriles was catalyzed by squaramide catalyst, and the corresponding spirocyclic products were obtained in good-to-high yields (up to 97%) with excellent stereoselectivities (up to >99% ee, >20:1 dr). At the same time, the practicality of the reaction was verified by the gram-scale preparation reaction.