Title
Absolute Configurations of Four Resorcylic Acid Lactones, Paecilomycins J − M, by CD/TDDFT Calculations
Author
Liang-Xiong Xu, Jing-Hua Xue, Ping Wu, Xiao-Ying You, Xiao-Yi Wei
Year
2013
Journal
Chirality
Abstract
The absolute configurations of four resorcylic acid lactones (RALs), paecilomycins J − M (1 − 3 and 5), were assigned by Time-Dependent Density-Functional Theory (TDDFT) calculations of their electronic circular dichroism (CD) spectra. The previously reported structure 4 for paecilomycin M was found to be incorrect and should be changed to structure 5. Analysis of structure-spectrum relationship for this group of RALs suggested that V′-shape conformations give type I CD spectra (two negative Cotton effects around 300 and 260 nm, a positive Cotton effect around 220 nm) while V-shape conformations yield type II spectra (signs of three Cotton effects were opposite to those in type I).
Instrument
J-810
Keywords
Circular dichroism, Absolute configuration