Isobutyraldehyde Lilial 2-Methylundecanal is an organic compound that is found naturally in kumquat peel oil.

The first route, like Darzens, involves converting methyl nonyl ketone to its glycidate by allowing it to react with alkyl chloroacetate.

[6] The second method for the synthesis of 2-methylundecanal begins with the conversion of undecanal to 2-methyleneundecanal by allowing it to react with formaldehyde in the presence of base.

The chiral hydrazones are then metalated with lithium diisopropylamide (LDA) and alkylated with a slight excess of dimethyl sulfate.

[7] 2-Methylundecanal is used widely as a fragrance element in soaps and detergents as well as in the perfume industry to give conifer notes, fir in particular, but is also used in fantasy compositions.