SEARCH Articles Figures Tables 2-Hydroxy-3-methyl- -4-hexenoic acid 3- -5-hexenoates 4-Hexenoic acid, 2-acetyl-2-methyl-6-bromoethyl ester 4-Hexenoic acid, 2-acetyl-2-methyl-6-bromoethyl ester cyclization From 4-Methyl-3-hexenoic acid Hexenoic acid Methyl 3-hexenoate