“…The grayananes are the major type of Ericaceae diterpenoids, while epoxygenated grayanane diterpenoids are relatively rare. To date, approximately 55 epoxygrayanane diterpenoids have been reported, including 28 2,3-epoxygrayananes, ,, a 2,3:11,16-diepoxygrayanane, 11 5,9-epoxygrayananes, ,,, five 6,10-epoxygrayananes, ,, a 9,10-epoxygrayanane, a 1,7-epoxygrayanane, a 2,10-epoxygrayanane, a 15,16-epoxygrayanane, an 11,16-epoxygrayanane, and five 10,14-epoxygrayananes . However, there is no report of 5,20-epoxygrayanane diterpenoids.…”