Determination of the Absolute Configurations of γ-Rubromycin and Related Spiro Compounds by Quantum Chemical CD Calculations

Abstract

The absolute configurations of the spiro compounds γ-and β-rubromycin (2 and 3), natural antibiotics derived from actinomycetes, have been elucidated as (S) by quantum chemical calculations of their chiroptical properties and comparisons with the respective experimental CD spectra. Surprisingly, their spiro centers show an absolute configuration opposite to that of heliquinomycin (1), the only related spiro compound for which the configuration has hitherto been as-

Absolute configurations of griseorhodins A and C

“…Interestingly, the griseorhodins A and C showed a different configuration at C-6. Other related compounds, such as heliquinomycin and γ-rubromycin, have been reported 12 from Streptomyces sp. with opposite configuration at their spiro centers (C-6a) ( R and S configuration respectively), showing the complex biosynthesis of this family of secondary metabolites.…”

Big Effects from Small Changes: Possible Ways to Explore Nature's Chemical Diversity

“…Streptomyces sp. (strain A1) produces the rubromycins 81 – 84 66, 67. When different supplements (such as CaCO 3 , Al 2 O 3 ) were added to the culture medium the metabolite pattern is shifted completely towards the production of streptazoline 85 and similar compounds (Scheme ) 68.…”

Atropo-Enantioselective Synthesis of the Natural Bicoumarin (+)-Isokotanin A via a Configurationally Stable Biaryl Lactone

“…The assignment of responsible transitions of the relevant calculated CD bands at 217 and 274 nm was performed by comparison of the experimental UV spectrum with the calculated one. For further details concerning quantum chemical calculation of chiroptical properties, see the corresponding section in ref 39…”