(1'R,E)-(+)-2-Methyl-4-(2',2',3'-trimethyl-cyclopent-3-enyl)-but-2-en-1-ol [ (+)-Madrol ] - fresh and strong sandalwood oil odor associated with green trees Odor Threshold = 51 ppb Bilke & Mosandl indicate that the (R)-enantiomer is exclusively responsible for the sandalwood-like odor, whilst the (S)-enantiomer has only a faint, non-specific odor. Buchbauer describes the (+)-isomer as Less similar to (-)-Madrol, sweet, and like the fragrance of roses Ref: Aida, et. al., United States Patent 6,084,138, July 4, 2000; Steffi Bilke, Armin Mosandl, Enantioselective analysis of 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-enol, 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-enal and -campholene aldehyde by capillary gas chromatography, Journal of Separation Science, Volume 24, Issue 10-11, Pages 819 - 822 (2001); see also Jerzy A. Bajgrowicz, Iris Frank, Georg Fráter, Michael Hennig, Helvetica Chimica Acta, Synthesis and Structure Elucidation of a New Potent Sandalwood-Oil Substitute, Volume 81, Issue 5-8, Pages 1349-1358 (1998) who indicate that the (R)-enantiomer is the active one; Gerhard Buchbauer, Philippine Lebada, Lucia Wiesinger, Petra Weiss-Greiler, Peter Wolschann, On the odor of the enantiomers of Madrol®, Chirality, Volume: 9, Issue: 4, Date: 1997, Pages: 380-385

(1'S,E)-(-)-2-Methyl-4-(2',2',3'-trimethyl-cyclopent-3-enyl)-but-2-en-1-ol [ (-)-Madrol ] - dry and weak sandalwood oil odor with a milky and floral note Odor Threshold = 424 ppb Bilke & Mosandl indicate that the (R)-enantiomer is exclusively responsible for the sandalwood-like odor, whilst the (S)-enantiomer has only a faint, non-specific odor. Buchbauer describes the (-)-isomer as Unambiguously like sandalwood, animalic Ref: Aida, et. al., United States Patent 6,084,138, July 4, 2000; Steffi Bilke, Armin Mosandl, Enantioselective analysis of 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-enol, 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-enal and -campholene aldehyde by capillary gas chromatography, Journal of Separation Science, Volume 24, Issue 10-11, Pages 819 - 822 (2001); see also Jerzy A. Bajgrowicz, Iris Frank, Georg Fráter, Michael Hennig, Helvetica Chimica Acta, Synthesis and Structure Elucidation of a New Potent Sandalwood-Oil Substitute, Volume 81, Issue 5-8, Pages 1349-1358 (1998) who indicate that the (R)-enantiomer is the active one; Gerhard Buchbauer, Philippine Lebada, Lucia Wiesinger, Petra Weiss-Greiler, Peter Wolschann, On the odor of the enantiomers of Madrol®, Chirality, Volume: 9, Issue: 4, Date: 1997, Pages: 380-385

(1'R,Z)-(+)-2-Methyl-4-(2',2',3'-trimethyl-cyclopent-3-enyl)-but-2-en-1-ol - Green, tomato, weak

Ref: Christian Chapuis, In the Quest for a Virtual Pseudo Receptor for Sandalwood-Like Odorants, Part I, Chemistry & Biodiversity, Volume 1, Issue 7, Date: July 2004, Pages: 980-1021

(1'S,Z)-(+)-2-Methyl-4-(2',2',3'-trimethyl-cyclopent-3-enyl)-but-2-en-1-ol - Woody, sandalwood, milk, very weak

Ref: Christian Chapuis, In the Quest for a Virtual Pseudo Receptor for Sandalwood-Like Odorants, Part I, Chemistry & Biodiversity, Volume 1, Issue 7, Date: July 2004, Pages: 980-1021

Ionones, Irones, Damascones & Structurally Related Odorants

Acyclics (Alcohols, Esters, Acids, Aldehydes)

Lactones

Sesquiterpenoid Related Odorants