SEARCH Articles Figures Tables 2- -2-alkenoate 5-alken 2-alkenoic acid 2-alkenal 2-alkenoic acid 2-alkenal 3-alkenoic acid 3-alken-3-olide 3-alkenoic acid alkene 3-alkenoic acid alkene 4- Alkenoic acids Alkenes acidity