Cyclopropyl for <i>Gem</i> ‐Dimethyl: Synthesis and Olfactory Properties of Linear Musks with Cyclopropyl Spacers**

Linear musks with cyclopropylmethyl spacers in place of 2‐methylpropyl spacers were designed, synthesised and evaluated olfactorily. Their synthesis commenced from commercially available 1‐(3′, 3′‐dimethylcyclohexyl)ethanone (Herbac) and 3‐methyl benzaldehyde via the corresponding methyl carbinols, Cyclodumol and 1‐( m ‐tolyl)ethan‐1‐ol, which were esterified with a protected glycolic acid and then transformed into the corresponding cyclopropyl compound by Tebbe olefination in tandem with Simmons–Smith cyclopropanation. After deprotection and esterification with various short‐chain carboxylic acids, their qualitative olfactory evaluation revealed that fusing the gem ‐dimethyl groups into a cyclopropyl ring retains and even intensifies the musk scent. Methylation of the cyclopropyl ring however completely erases not only the distinct musk character but virtually any odour.