Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• Abstract We confirm the previously revised stereochemistry of spiroviolene by X-ray crystallographically characterizing a hydrazone derivative of 9-oxospiroviolane, which is synthesized by hydroboration/oxidation of spiroviolene followed by oxidation of the resultant hydroxy group. An unexpected thermal

• boron migration occurred during the hydroboration process of spiroviolene that resulted in the production of a mixture of 1α-hydroxyspiroviolane, 9α- and 9β-hydroxyspiroviolane after oxidation. The assertion of the cis-orientation of the 19- and 20-methyl groups provided further support for the revised

• cyclization mechanism of spiroviolene. Keywords: boron migration; diterpene; spiroviolene; stereochemistry; Introduction Terpenes represent one of the most fascinating families of natural products due to their structural complexity and diversity, as well as their indispensable biological functions that

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• gets close, it would easily form a C–C bond. Therefore, we believe that no other transannular cation–π interactions need to be considered in this system. In systems without cation–π interactions, such as in the biosynthesis of variediene [39] and spiroviolene [40], bonds around the secondary

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• Streptomyces pristinaespiralis [26], spiroviolene synthase from Streptomyces violens [27], micromonocyclol synthase from Micromonospora marina [28], α-amorphene synthase from Streptomyces viridochromogenes [29][30], epi-cubenol synthase from S. griseus [31], germacrene A synthase from M. marina [32], and 7-epi

• ) and for the enzyme from S. catenulae the RY pair is modified to RF (Figure S39, Supporting Information File 1). The closest characterised homolog of these enzymes is the spiroviolene synthase from S. violens [27] with amino acid sequence identities between 32% and 36%. All four enzymes did not accept