Syntheses, Structures, and Sensory Characteristics of the Perfume Ingredient Majantol and Its Analogs Sila-majantol and Germa-majantol:  A Study on C/Si/Ge Bioisosterism<sup>§</sup>

The perfume ingredient majantol [2,2-dimethyl-3-(3-methylphenyl)propan-1-ol (<b>1a</b>)] and its silicon- and germanium-containing analogs sila-majantol [(hydroxymethyl)dimethyl(3-methylbenzyl)silane (<b>1b</b>)] and germa-majantol [(hydroxymethyl)dimethyl(3-methylbenzyl)germane (<b>1c</b>)], respectively, were synthesized from <i>i</i>-PrC(O)Ph (four steps, → <b>1a</b>), Me<sub>2</sub>Si(CH<sub>2</sub>Cl)Cl (three steps, → <b>1b</b>), or Cl<sub>3</sub>GeCH<sub>2</sub>Cl (four steps, → <b>1c</b>). The structures of the C/Si/Ge analogs <b>1a</b>/<b>1b</b>/<b>1c</b> were determined by crystal structure analyses and computational studies [RI-MP2 calculations (TZVP level)]. The odor of majantol (<b>1a</b>) was found to be strong fresh-floral, aqueous-aldehydic, and characteristic of lily-of-the-valley flowers, whereas that of sila-majantol (<b>1b</b>) was considerably less intense than that of <b>1a</b>. It lacked the aqueous-aldehydic freshness, but possessed nevertheless the characteristic lily-of-the-valley odor, but it was more terpineol-like. The odor of germa-majantol (<b>1c</b>) was very weak and not characteristic; the majantol impression could be recognized only as a shade.