ipso-Cyclization: an emerging tool for multifunctional spirocyclohexadienones

Abstract

ipso-Annulation represents an attractive approach to synthesize a variety of spirocyclic compounds having a quaternary carbon center. Furthermore, these compounds also serve as a handy synthon for the construction of various complex molecules. This review presents various useful approaches for the intramolecular ipso-cyclization to afford a wide range of spirocyclohexadienones. In addition, the utility of spirocyclic compounds towards the synthesis of complex molecules is also included.

Visible‐Light‐Promoted Intermolecular Oxidative Dearomatization of β‐Naphthols with N‐Hydroxycarbamates

“…As an important class of transformations, their dearomatization reactions provide a direct avenue for cyclic enones, which are widely embedded in natural products and biologically active molecules . Of particular note, oxidative dearomatization reactions have emerged as attractive methods given their atom‐economic nature and useful products generated therein ,,,,,,. Accordingly, tremendous efforts have been made on the oxidative dearomatization of phenols and naphthols.…”

Recent Advances in Intramolecular Metal‐Free Oxidative C–H Bond Aminations Using Hypervalent Iodine(III) Reagents

“…Intramolecular ipso ‐annulation has received considerable attention in organic synthesis, for efficient carbon–nitrogen (C‐N) bond formation in single operation by hypervalent iodine(III) reagents. In this regard recently Reddy et al focussed on review on ipso ‐Cyclization for synthesis of spirocyclohexadienones, by using hypervalent iodine(III) reagents or organo iodoarenes for C‐N bond formations , , , , , …”

Synthesis of spiro-cyclohexendienone-gamma-lactams via free-radicals and study of thermal regioselective spirocyclization

“…Indeed, in this year, C.R. Reddy and co-workers reviewed masterfully the most recent advances on the synthesis of spyro-cyclohexendienone--lactams and other related spiroheterocycles via ionic and free-radical mediated ipso-spirocyclizations [9]. Thus, we herein report a study of regioselectivity via free-radical mediated spirocyclization toward the synthesis of a couple of spiro-cyclohexendienone--lactams from a xanthate precursor, which was synthesize stepwise.…”