Assignment of the absolute configuration of (+)-5,5′,6,6′-tetrahydro-7,7′-spiro[7H-cyclopenta[b]pyridine], a new inherently chiral spiropyridine, by a nonempirical analysis of its circular dichroism spectrum

The absolute configuration of (+)-spiropyridine 1, obtained in its enantiopure form by chromatographic resolution of the racemate upon the CSP Chiralcel AD, has been assigned as (aS) by simulating the ECD spectrum in the range 320–235 nm both by coupled oscillator (DeVoe) and TD DFT/B3LYP/6-31G∗ calculations.

Graphical abstractCompound (+)-1 has an (aS)-absolute configuration.Figure optionsDownload full-size imageDownload as PowerPoint slide

5,5′,6,6′-Tetrahydro-7,7′-spiro[7H-cyclopenta[b]pyridine]C15H14N2[α]D = +4.2 (c 0.46, EtOH)Source of chirality: chromatographic resolution upon Chiralcel ADAbsolute configuration: (aS)