SEARCH Articles Figures Tables 6-Lactones optically active chiral base Chiral lactone Chiral lactone Chiral lactone intermediates Chiral lactone optical resolution Chiral lactone product Chiral lactones synthesis Chiral pheromone lactones Diastereofacial selectivity chiral lactones Lactone chirality Lactonization, chiral ammonium Lactonization, chiral ammonium phenoxide Prelog-Djerassi lactonic acid use of chiral reagent