Squaric acid as an organocatalyst for Knoevenagel condensation and 1,6-conjugate addition reactions

Abstract

Catalysts play an integral role in rationalizing several organic reactions despite suffering major challenges like poor efficiency, high cost and toxicity. In this work, we have reported a green, cost effective and highly efficient squaric acid as an organocatalyst for catalyzing two of the most vital organic reactions, Knoevenagel condensation and 1,6-conjugate addition reactions. Under our optimized conditions, the organocatayst showed excellent yields of up to 94% for both the reactions with an extensive substrate scope and excellent reusability for multiple reaction cycles. In addition, the catalytic efficacy of squaric acid was showcased by employing it in the synthesis of 2-amino-4H-chromene derivatives.