A Pair of New Polyketide Enantiomers from Three Endolichenic Fungal Strains Nigrospora sphaerica, Alternaria alternata, and Phialophora sp.

A pair of new enantiomeric polyketides, (-)- and (+)-nigrosporaol A (1a and 1b), along with one related known compound, (+)-alternarienoic acid (2), were isolated from three endolichenic fungal strains, Nigrospora sphaerica (No.83-1-1-2), Alternaria alternata (No.58-8-4-1), and Phialophora sp.(No.96-1-8-1). Their structures, including the absolute configurations, were elucidated on the basis of spectroscopic methods, X-ray diffraction analysis, and the modified Mosher's method.