Efficient Synthesis of 3-Aryl-5-chloroindan-1-ones via Free Radical–Mediated Intramolecular Cyclization

Abstract

An efficient free radical–mediated intramolecular cyclization strategy has been developed for the synthesis of 3-aryl-5-chloroindan-1-ones. Variously substituted 2,4-dichloroenones afforded 3-aryl-5-chloroindan-1-ones in quantitative yields upon intramolecular cyclization under free radical conditions.

GRAPHICAL ABSTRACT

Keywords:

• AIBN
• ⁿ Bu₃SnH
• enone
• free radicals
• intramolecular cyclization

ACKNOWLEDGMENTS

The authors are obliged to the Higher Education Commission, government of Pakistan, for generous support of a research project (HEC 20-809), fellowship to Aeysha Sultan (074-141-Ps4-435), and IRSIP award and financial assistance for ESI MS, LR EIMS, and NMR analyses. The authors are also grateful to the Department of Physics, University of Sargodha, for the single-crystal XRD facility.

Notes

^a Equivalents to 4a.

^b Drop-wise addition of ⁿ Bu₃SnH to a refluxing solution of enone 4a and AIBN in PhH.

^C Dropwise addition of enone 4a to vigorously refluxing solution of AIBN and ⁿ Bu₃SnH in PhH.