Structure 1 was reported for a novel antifungal agent, L-657,398, isolated from fermentations of Aspergillus ochraceusP However, the relative and absolute stereochemistry of this compound were not reported. We have isolated a compound with the same structure (exclusive of stereochemistry) from fermentations of Preussia sp., by extraction of the mycelial cake with methanol and purification of th...

Pheromonal communications are heavily dependent on the stereochemistry of pheromones. Their enantioselective syntheses could establish the absolute configuration of the naturally occurring pheromones, and clarified the unique relationships between absolute configuration and bioactivity. For example, neither the (R)- nor (S)-enantiomer of sulcatol, the aggregation pheromone of an ambrosia beetle...

X-ray crystallography unequivocally confirmed the stereochemistry of the 2-C-methyl group in the title mol-ecule, C(10)H(16)O(5), in which the 1,5-lactone ring exists in a boat conformation. The absolute stereochemistry was determined by the use of d-ribose in the synthesis. The crystal exists as O-H⋯O hydrogen bonded chains of mol-ecules running parallel to the a axis with each mol-ecule actin...

X-ray crystallography unequivocally confirmed the stereochemistry of the C atom at position 2 in the carbon scaffold of the title mol-ecule, C(10)H(18)O(4). The pyran-ose ring exists in a chair conformation with the methyl group on the C atom in the 2 position in an equatorial configuration. The absolute stereochemistry was determined from the starting material. The crystal structure consists o...

The paper updates Isler's monograph of 1971 regarding the structures of naturally occurring carotenoids, their chemical reactions and their stereochemistry. Around ninety new structures are reported, including the new series of C30-carotenoids, enolized /3-diketones and several carotenoids with 2-hydroxy 3-rings. Progress in stereochemistry resulting in the configurational assignment of eleven ...

Higenamine is a tetrahydroisoquinoline present in several plants that has β-adrenergic receptor agonist activity. Study of the biosynthesis of higenamine has shown the participation of norcoclaurine synthase, which controls the stereochemistry to construct the (S)-isomer. However, when isolated from nature, higenamine is found as the racemate, or even the (R)-isomer. We recently reported the is...