Electronic-State Switching Strategy in the Photochemical Synthesis of Indanones from o-Methyl Phenacyl Epoxides

Abstract

An electronic excited-state switching strategy has been utilized to control the selectivity of a key photochemical step in the total synthesis of indanorine. The excited-state character of 4,5-dimethoxy-2-methylphenacyl epoxide was changed from an unfavorable (3)π,π* state to a productive (3)n,π* state by a temporary structural modification, resulting in a relatively efficient and high-yielding formation of an indanone derivative. The corresponding structural modification was selected on the basis of quantum chemical calculations prior to the synthesis.

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

“…An electronic excited-state switching strategy has been utilized to control the selectivity of this reaction in the total synthesis of indanorine. 72 The excited-state character of the parent compound was changed to create a productive 3 n ,π* state by a temporary structural modification selected on the basis of quantum chemical calculations prior to the synthesis. In addition, competition of a triplet-state photoenolization reaction with a photo-Favorskii rearrangement for ( o / p )-hydroxy- o -methylphenacyl esters was shown to depend on the water content of the solvent.…”

Synthesis of Flavone Derivatives via N-Amination and Evaluation of Their Anticancer Activities

“…The mixture was subsequently filtered and the pure product was obtained after removing the solvent under vacuum distillation (without further purification). By following a method analogous to that described in Reference [12,13], 2b was easily obtained. The intermediate chalcone 3 was achieved via aldol condensation between 1a and 2b at 40 °C with NaOH (aq 40%) as the base [14,15].…”

“…The solvent was removed under reduced pressure to get the crude product, which was purified through flash column chromatography to afford compound 2b (white solid; yield 95%). Other data can be found in Reference [13].…”

Recent Advances in the Synthesis of Indanes and Indenes

“…Functionalized indanones were recently synthesized by photochemical ring opening of epoxide derivatives, such as 157 . This method was applied to the total synthesis of indanorine 158 , an indanone derivative with antiproliferative activity (Scheme ) …”

“… Total synthesis of biologically active indanorine 158 by photochemical ring expansion of epoxide 157 …”