Furthermore, the 1 H NMR spectrum of 1 also exhibited the presence of a 2″-isopropenyl dihydrofuran ring—a methyl group singlet signal at δ H 1.72 (3H, s, H-5″) and two broad singlets for an exomethylene group signal at δ H 4.82 (1H, s, Ha-4″) and 5.03 (1H, s, Hb-4″).
Source: wiktionary