Absolute configuration of phomactatriene diterpenoids obtained by Wagner‐Meerwein rearrangement of epimeric verticillols

The epimeric diterpenes (+)‐(1S,3E,7E,11S,12S)‐verticilla‐3,7‐dien‐12‐ol (1), isolated from Bursera suntui, and (+)‐(1S,3E,7E,11S,12R)‐verticilla‐3,7‐dien‐12‐ol (2), isolated from Bursera kerberi, gave the same Wagner‐Meerwein rearrangement product (−)‐(1E,4Z,8Z,11S,12R)‐phomacta‐1,(15)4,8‐triene (3...

Full description

Saved in:
Bibliographic Details
Published in:Chirality (New York, N.Y.) N.Y.), 2019-11, Vol.31 (11), p.934-946
Main Authors: Río‐Chávez, Ángel A., García‐Gutiérrez, Hugo A., Román‐Marín, Luisa U., Beiza‐Granados, Lidia, Cerda‐García‐Rojas, Carlos M., Joseph‐Nathan, Pedro, Hernández‐Hernández, Juan D.
Format: Article
Language:English
Subjects:
Absolute configuration
Bursera
Circular dichroism
Computer simulation
Configurations
Density functional theory
Dichroism
Diterpenes
Epoxidation
Molecular modelling
Optimization
phomactanes
reaction intermediates
Taxanes
verticillanes
vibrational circular dichroism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The epimeric diterpenes (+)‐(1S,3E,7E,11S,12S)‐verticilla‐3,7‐dien‐12‐ol (1), isolated from Bursera suntui, and (+)‐(1S,3E,7E,11S,12R)‐verticilla‐3,7‐dien‐12‐ol (2), isolated from Bursera kerberi, gave the same Wagner‐Meerwein rearrangement product (−)‐(1E,4Z,8Z,11S,12R)‐phomacta‐1,(15)4,8‐triene (3). The Et2O:BF3‐induced transformations evidence that verticillenes and phomactanes, both containing the bicyclo[9.3.1]pentadecane skeleton, are biogenetically related through the verticillen‐12‐yl cation (A+), which also is a key intermediate in the biosynthetic pathways to generate antitumor taxanes. Molecular modeling using the Monte Carlo protocol, followed by density functional theory (DFT) geometry optimization employing the hybrid functionals B3LYP and B3PW91, both with the DGDZVP basis set, secured the configuration of 3 as followed from the good agreement between the calculated and experimental vibrational circular dichroism spectra. Similar DFT calculations allowed determining the absolute configuration of (+)‐(1R,4R,5R,8S,9S,11S,12R,15R)‐1,15:4,5:8,9‐triepoxyphomactane (9), which surprisingly derives from epoxidation of the second minimum energy conformer of 3.
ISSN:0899-0042
1520-636X
DOI:10.1002/chir.23061