RC-0 IUPAC Names R for Ketones Replace -e with -one.Indicate the position of the carbonyl with a number. Number the chain so that carbonyl carbon has the lowest number. For cyclic ketones the carbonyl carbon is assigned the number 1. Chapter 18 Chapter 18 4 IUPAC Names for Ketones • Replace -e with -one. Indicate the position of the carbonyl with a number. • Number the chain so that carbonyl carbon has the lowest number. • For cyclic ketones the carbonyl carbon is assigned the number 1. =>