Paecilomycines A and B, Novel Diterpenoids, Isolated from Insect‐Pathogenic Fungi Paecilomyces sp. ACCC 37762

Two new diterpenoids, named paecilomycine A (1) and paecilomycine B (2), including a novel skeleton with a five-membered lactone ring, together with three known labdane diterpenoids, rel-(1R,3S,4aS,5R,8aS)-5-[(3E)-4-carboxy-3-methylbut-3-en-1-yl]decahydro-3-hydroxy-1,4a-dimethyl-6-methylidenenaphthalene-1-carboxylic acid (3), botryosphaerin E (4), and agathic acid (5), were isolated from solid culture of the insect pathogenic fungi strain Paecilomyces sp. The structures of all compounds were established on the basis of comprehensive spectroscopic studies. The relative configurations of 1 and 2 were determined by single-crystal X-ray diffraction analyses.