The enantiomers of Iralia®: preparation and odour evaluation

The enantiomers of methyl ionones 1 and 2 were prepared by an enzyme-catalysed approach. Their odour properties were evaluated by skilful perfumers.

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(R,E)-3-Methyl-4-((S)-2,6,6-trimethyl cyclohex-2-enyl)but-3-en-2-yl acetateC16H26O2Ee = 98%[α]D24=-203.1 (c 1.05, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R,1′S)

(R,E)-3-Methyl-4-((S)-2,6,6-trimethyl cyclohex-2-enyl)but-3-en-2-olC14H24OEe = 98%[α]D24=-321.5 (c 1.08, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R1′,S)

(R,E)-3-Methyl-4-((R)-2,6,6-trimethyl cyclohex-2-enyl)but-3-en-2-yl acetateC16H26O2Ee = 94%[α]D24=+278.8 (c 1.10, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R,1′R)

(R,E)-3-Methyl-4-((R)-2,6,6-trimethyl cyclohex-2-enyl)but-3-en-2-olC14H24OEe = 94%[α]D24=+308.3 (c 0.95, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R,1′R)

(R,E)-1-((S)-2,6,6-Trimethyl cyclohex-2-enyl)pent-1-en-3-olC14H24OEe = 98%[α]D24=-289.3 (c 1.21, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R,1′S)

(R,E)-1-((S)-2,6,6-Trimethyl cyclohex-2-enyl)pent-1-en-3-olC16H26O2Ee = 98%[α]D24=-178.5 (c 1.14, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R,1′S)

(S,E)-3-Methyl-4-(2,6,6-trimethyl cyclohex-2-enyl)but-3-en-2-oneC14H22OEe = 98%[α]D24=-450 (c 1.31, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2S)

(S,E)-1-(2,6,6-Trimethyl cyclohex-2-enyl)pent-1-en-3-oneC14H22OEe = 98%[α]D24=-397.1 (c 1.20, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2S)

(R)-3-Oxobutan-2-yl benzoateC11H12O3Ee = 93%[α]D24=-33.1 (c 1.16, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R)

(R)-1-Oxobutan-2-yl benzoateC11H12O3Ee = 95%[α]D24=+41.0 (c 1.0, CHCl3)Source of chirality: lipase-mediated transesterificationAbsolute configuration: (2R)