19777
A series of novel oleanane - type pentacyclic triterpenoids bearing a boronate ester moiety at C3 have been synthesized by palladium - catalyzed cross - coupling of bis ( pinacolato ) diboron with vinyl triflates , in the presence of base , and these compounds were fully characterized by 1D and 2D NMR techniques .
 oleanane, triterpenoids, boronate ester, palladium, bis ( pinacolato ) diboron, vinyl triflates
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 oleanane, triterpenoids, boronate ester, palladium, bis ( pinacolato ) diboron, vinyl triflates