Synthesis of 9,10-Phenanthrenequinones by Photocyclization of Derivatives of Benzoins: Scope and Limitation of the Methodology

Abstract

Symmetric 9,10-phenanthrenequinones with methyl, methoxy, and chloro substituents at the 3 and 6 positions have been synthesized by photocyclization of 4,5-bis-(aryl)-2-phenyl-1,3,2-dioxaboroles and 2,3-diaryldioxenes followed by oxidative hydrolysis.

Notes

The yield of benzoin was 83%, 4,4′-dimethoxibenzoin was 75%, 4,4′-dichlorobenzoin was 67%, 4,4′-dimethylbenzoin was 61%, and 4-methoxy benzoin was 25%.

This signal disappeared upon addition of D₂O.

No ketal was obtained.

The same melting point and infrared spectra.