Abstract
In the course of our mechanistic studies of mycoparasitism between Lambertella spp. (the parasite) and Monilinia fructigena (M. f., the host) on apple fruits, we isolated known lambertellin (1) and new spirobutenolides lambertellols A (2), B (3). Lambertellols were detected only when the host M. f. co-inhabited in the broth of M. f. Lambertellols 2, 3 were readily interconverted and gradually decomposed into 1. Our total syntheses enable the SAR studies to disclose that 1 should be the real active species and 2 and 3 are diffusible precursors. In order to rationally explain these observations, we performed dynamic analyses of the metabolites to disclose a novel alleropathy ‘Lambertellin system’ as described in this article. This mechanism also accords with the progress of ‘Natsu-Nenju’ disease on apple fruits, which is known to be a mysterious phyto-disease because of two unique stages of its lifecycle, anamorphic (asexual) and teleomorphic (sexual). Only organic chemistry based investigations could approach the final conclusion in this particular case.
