Determination of the absolute configuration of the natural product Klaivanolide via density functional calculations of vibrational circular dichroism (VCD).

The absolute configuration (AC) of the antiprotozoal lactone, Klaivanolide, 1, from Uvaria klaineana, has been determined using Vibrational Circular Dichroism (VCD) spectroscopy. The experimental VCD spectrum of the (+) enantiomer of 1 was measured. To analyze the AC of (+)-1, the conformationally-averaged VCD spectrum of 7-S-1 was calculated using density functional theory (DFT) and the GAUSSIAN 03 program. The B3PW91/TZ2P conformationally-averaged VCD spectrum of 7-S-1 proves that the AC of 1 is 7-S-(+).