Stereoselective Synthesis of Polyfunctionalized Nitrothianes: Enhancement of Stereoselectivity by Microwaves

Abstract

The Michael addition of nitromethane to (Z,Z)-2,2′-thiobis(1,3-diarylprop-2-en-1-ones) in the presence of NaOEt in dimethylformamide (DMF)/alcohol under thermal conditions affords a diastereomeric mixture of 2a,6e-diaroyl-3a,5e-diaryl-4e-nitrothianes and 2e,6e-diaroyl-3e,5e-diaryl-4e-nitrothianes with a dr of ∼3:1/4:1 respectively. This reaction under microwave irradiation in DMF/alcohol afforded solely 2a,6e-diaroyl-3a,5e-diaryl-4e-nitrothianes, disclosing enhancement of stereoselectivity by microwaves.

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GRAPHICAL ABSTRACT

Keywords:

• Michael addition
• microwave irradiation
• nitrothianes
• stereoselectivity
• 2,2′-thiobis(1,3-diarylprop-2-en-1-ones)

ACKNOWLEDGMENTS

S. R. and S. P thank the University Grants Commission (UGC) for funds under major research projects. S. R. and B. V. thank the secretary and principal, Fatima College, Madurai, for providing facilities. B. V. thanks the Council of Scientific and Industrial Research for a senior research fellowship.