Tertiary Alcohols with Earthy Odor

A series of highly hindered tertiary alcohols was synthesized to define the minimun structural requirements for earthy smelling molecules. Some of the compounds described are endowed with a strong pure earthy note, similar to the odor of geosmin. Medium size (10−14 major atoms) and the presence of highly branched alkyl radicals bound to the carbinol center seem to represent the molecular parameters best related to the earthy odor. A cyclic system is not an essential requirement for this type of odor. Several among the best earthy smelling compounds described in this work are not asymmetric molecules; this result confirms previous reports indicating that the earthy odor is not related to the chirality of the molecules.