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Synthesis 2002(15): 2243-2253
DOI: 10.1055/s-2002-34847
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© Georg Thieme Verlag Stuttgart · New York

Design, Synthesis and Structure-Odor Correlation of Novel Spiro[4.5]-decan-2-ones

Philip Kraft*, Riccardo Cadalbert
Givaudan Dübendorf AG, Überlandstrasse 138, 8600 Dübendorf, Switzerland
Fax: +41(1)8242926; e-Mail: philip.kraft@givaudan.com;
Further Information

Publication History

Received 12 June 2002
Publication Date:
21 October 2002 (online)

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Abstract

Dehydration and Rupe rearrangement of 2-(3,3-dimethylcyclohexyl)hex-3-yne-2,5-diol (9) furnished as a 3% byproduct the intense vetiver-like smelling 4,7,7-trimethyl-1-methylene­spiro[4.5]decan-2-one (11). Motivated by the commercial importance of vetiver oil and the lack of synthetic substitutes as well as the lack of insight into the structural requirements for vetiver odorants, an efficient synthetic route to vetiver-like smelling compounds was developed. It consists of Wittig-Horner-Emmons reaction of diverse cycloalkanones with triethyl 2-phosphonopropionate, subsequent Grignard reaction with in situ conversion to the trienolate, and classical Nazarov cyclization of the resulting dienones. This route not only leads to 11 in 61% yield in the final Nazarov cyclization, but also to 16 analogs, which provide insight into both, the Nazarov reaction and the structure-odor relationship of vetiver odorants. Other vetiver-like smelling compounds discovered include (1RS,4SR,5SR)-1,4,7,7-tetramethylspiro[4.5]decan-2-one (16), 4-methyl-1-methylenespiro[4.6]undecan-2-one (30) and 4-methyl-1-methylenespiro[4.7]dodecan-2-one (31).

Key words

cyclizations - khusimone - odor-structure correlation - spiro compounds - vetiver