Birhodomolleins D and E, two new dimeric grayanane diterpenes with a 3-O-2′ linkage from the fruits of Rhododendron pumilum

Two dimeric grayanane diterpenes with a novel 3-O-2′ linkage, birhodomolleins D (1) and E (2), were isolated and structurally elucidated from the fruits of Rhododendron pumilum. Their structures were fully determined by comprehensive analysis of spectroscopic data.