A process for augmenting or enhancing the aroma or taste of a consumable material selected from the group consisting of perfume compositions, colognes, and perfumed articles, comprising the step of adding to consumable material an aroma augmenting or enhancing quantity of at least one compound defined according to the structure:
- ##STR130## wherein one of the dashed lines represents a carbon-carbon double bond and the other of the dashed lines represents a carbon-carbon single bond;
- wherein R.sub.4 represents methyl or ethyl;
- wherein one of R.sub.1, R.sub.2 and R.sub.3 represents 2-methyl-1-propenyl or 2-methyl-1-propylidenyl;
- and the other of R.sub.1, R.sub.2 and R.sub.3 represent hydrogen;
- with the provisos that:
- (i) when the dashed line at the 3-4 position is a double bond, then R.sub.3 is hydrogen or 2-methyl-1-propenyl;
- (ii) when the dashed line at the 2-3 position is a double bond, then R.sub.2 is hydrogen or 2-methyl-1-propenyl;
- (iii) when R.sub.4 is ethyl, then R.sub.2 is methyl and the double bond is at the 2-3 position;
- and
- (iv) when R.sub.4 is methyl, then R.sub.2 is hydrogen;
- 2-methyl-1-propenyl or 2-methyl-1-propylidenyl;
- with the members of said genus being novel compounds when R.sub.4 is ethyl or when R.sub.4 is methyl and the double bond is at the 3-4 position or when R.sub.4 is methyl and the double bond is at the 2-3 position with R.sub.3 being hydrogen.