Synthesis of Dimedone-Annelated Heterocycles: Regioselective Heterocyclization of 2-(Cyclohex-2′-enyl)-5,5-dimethyl-3-hydroxy cyclohex-2-enone

Abstract

2-(Cyclohex-2′-enyl)-5,5-dimethyl-3-hydroxycyclohex-2-enone undergoes regioselective heterocyclization to give bridged heterocycles 5a,b and 7 on treatment with pyridine hydrotribromide or hexamethylenetetramine hydrotribromide (1 h); or elemental bromine (7 h); N-iodosuccinimide in acetonitrile at 0–5°C (1 h) and conc. H₂SO₄ at 0–5°C (2 h), respectively.

Acknowledgments

We thank the CSIR (New Delhi) for financial assistance. P. K. B. is thankful to UGC (New Delhi) for a Junior Research Fellowship and S. K. S. is grateful to CSIR (New Delhi) for a fellowship.