Alkyl-Substituted δ-Lactones Derived from Dihydrojasmone and Their Stereoselective Fungi-Mediated Conversion: Production of New Antifeedant Agents.

Anna Gliszczyńska,Maryla Szczepanik,Katarzyna Dancewicz,Damian Semba,Beata Gabryś

doi:10.3390/molecules21091226

Abstract

A chemoenzymatic method was applied to obtain optically pure alkyl-substituted δ-lactones. First, chemical Baeyer–Villiger oxidation of dihydrojasmone (1) was carried out, affording two new alkyl-substituted δ-lactones: 3,4-dihydro-5-methyl-6-pentyl-2H-pyran-2-one (2) and 5-methyl-6-pentyl-1,13-dioxabicyclo[4.1.0]heptan-2-one (3). In the next step, fungal strains were investigated as biocatalysts to enantioselective conversion of δ-lactones (2) and (3). The fungal cultures: Fusarium culmorum AM10, Fusarium equiseti AM15 and Beauveria bassiana AM278 catalyzed the stereoselective hydration of the double bond of lactone (2) (ee = 20%–99%) while Didymosphaeria igniaria KCh6670 proved to be the best biocatalyst for the reduction of carbonyl group in the epoxylactone (3) (ee = 99%). In both cases, chiral oxyderivatives were obtained in low to high yields (7%–91%). The synthetic lactones (2), (3) and its derivatives (4), (5) were tested for their antifeedant activity towards larvae and adults of lesser mealworm (Alphitobius diaperinus Panzer) and peach potato aphid (Myzus persicae [Sulzer]) and some of them were active towards studied insects.

Highlights

Over the last few decades, numerous research papers about isolation and synthesis of alkyl-substituted δ-lactones have been widely published in the literature [1,2,3]
Taking into consideration the broad spectrum of alkyl-substituted δ-lactones properties, it was purposeful to check whether lactone moiety introduced into the structure of dihydrojasmone
The Baeyer–Villiger oxidation of commercially available dihydrojasmone (1) with meta-chloroperbenzoic acid (m-CPBA) generated the mixture of two new δ-lactones: 3,4-dihydro-5-methyl-6-pentyl-2H-pyran-2-one (2) and 5-methyl-6-pentyl-1,13dioxabicyclo[4.1.0]heptan-2-one (3) as the products (Figure 1) that were separated by silica-gel column chromatography

Summary

Introduction

Over the last few decades, numerous research papers about isolation and synthesis of alkyl-substituted δ-lactones have been widely published in the literature [1,2,3] These compounds have been isolated from various natural sources: plants, marine organisms and terrestrial animals [4,5,6]. Chiral alkyl-substituted δ-lactones as the carriers of specific odor have considerable industrial value in the flavor, cosmetic and food industries. They are a large group of compounds that play important roles in insect’s lives as pheromones, and are the key intermediates for the synthesis of other biologically active compounds.

Methods

Results

Conclusion