The molecular ions fragmentation canals of substances registered by means of the GC-MS method in the media of Lentinula edodes (shiitake) basidiomycete submerged cultivation in the presence of diacetophenonylselenide have been substantiated. At the B3LYP/6-311++G(3df,3pd) and UB3LYP/6-311++G(3df,3pd) level, involving the NBO analysis and the R. F. W. Bader’s «Atoms in Molecules» quantum theory (QTAIM), isomeric transformations of dihydrofurans have been considered.
