Abstract
Triggered by a seemingly inconsistent twisting direction in the atroposelective ring cleavage reaction of biaryl lactones by using the ‘lactone concept’, the absolute axial configurations of the most important phenylanthraquinones, knipholone ( 1), and knipholone anthrone ( 2) were reassigned on the basis of renewed quantum chemical circular dichroism (CD) calculations using advanced, higher-level methods, viz. a time-dependent DFT (TDDFT) and a multireference configurational interaction approach (DFT/MRCI). Additional confirmation of the new configurational assignment of 1 and 2 was achieved by their stereochemically unambiguous interconversion, and further corroborated by the transformation of 1 into an ‘leuco’ phenylanthracene derivative 3, i.e., a compound with a substantially different chromophore, whose absolute configuration was independently assigned again by quantum chemical CD calculations. Accordingly, the dextrorotatory enantiomer of knipholone, (+)- 1, and its anthrone, (+)- 2, has the P-configuration, while the laevorotatory forms, (−)- 1 and (−)- 2 (which likewise exist in nature), are M-configured. From this new configurational assignment, the absolute axial stereostructures of a whole series of further naturally occurring phenylanthraquinones may now be deduced.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
