Synthesis of Medium and Large Ring Compounds, XXXVIII. Ring Enlargement of Cyclodecanone by a Chiral Building Block: Synthesis and Olfactory Properties of (12R)‐(+)‐12‐Methyl‐13‐Tridecanolide

The title compound (+)‐3 was synthesized in four steps by ring enlargement of cyclodecanone (6) with the chiral building block 5. The protected hydroxy halide 5, easily prepared from commercially available (2S)‐(+)‐methyl 3‐hydroxy‐2‐methylpropanoate (4), was introduced by HMPA‐mediated enolate alkylation and subsequent formation of the cyclic enol ether 8. Ozonolysis and mild chemoselective reduction of the carbonyl function led to the optically active target molecule (+)‐3, which possesses a very interesting clear musk note with elegant sandalwood aspects.