Glycerol has been incorporated mid-chain into the polyketide soraphen A 1 at C-3, 4 and C- 11, 12; the pro-(S)-hydroxymethyl group of glycerol is lost and one of the hydrogens in the pro-(R)-hydroxymethyl group is retained at C-11 which excludes hydroxymalonate as the immediate precursor to the vicinal methoxy groups at C-11, 12.