Base-Promoted Synthesis of S-Arylisothiazolones via Intramolecular Dehydrative Cyclization of α-Keto- N-acylsulfoximines

Nikita Chakraborty; Bubul Das; Dinabandhu Barik; Kamal K Rajbongshi; Bhisma K Patel

doi:10.1021/acs.joc.3c02269

Base-Promoted Synthesis of S-Arylisothiazolones via Intramolecular Dehydrative Cyclization of α-Keto- N-acylsulfoximines

J Org Chem. 2024 Jan 5;89(1):778-783. doi: 10.1021/acs.joc.3c02269. Epub 2023 Dec 14.

Authors

Nikita Chakraborty¹, Bubul Das¹, Dinabandhu Barik¹, Kamal K Rajbongshi^{1

2}, Bhisma K Patel¹

Affiliations

¹ Department of Chemistry, Indian Institute of Technology Guwahati, North Guwahati 781039, India.
² Department of Chemistry, Handique Girls' College, Guwahati, Assam 781001, India.

PMID: 38096382
DOI: 10.1021/acs.joc.3c02269

Abstract

A base (Et₃N)-promoted synthesis of 1,4-diarylisothiazolones from α-keto-N-acylsulfoximines has been achieved. The reaction proceeds via α-hydrogen abstraction from sulfoximine, followed by an intramolecular nucleophilic attack at the keto carbonyl to form a tert-hydroxy isothiazolone intermediate. The 1,4-substituted isothiazolone is obtained after dehydration via an E1cB path. This one-pot synthesis of isothiazolinones has a broad substrate scope, has a high atom economy, and provides products with good yields. The ΔE_LUMO-HOMO is calculated using Gaussian 16 at the B3LYP/6-31G(d,p) level of theory.