Highest enol content will be shown by: [2024]
(4)
More is acidic strength of acidic hydrogen in ketone, more is the percent enol content. In (3) and (4), there is active methylene group hence acidic strength of enolisable H is more as compared to (1) and (2). In (4), because of −I effect of carbonyl group, acidic strength of H of active methylene group is more as compared to that in (3). Hence (4) has highest percent enol content.
