title: Design and enantioselective synthesis of Cashmeran odorants by using "enol catalysis".
abstract: Novel Cashmeran odorants were designed by molecular modeling. Their short syntheses involve a novel asymmetric Brønsted acid catalyzed Michael addition of unactivated α-substituted ketones. This key transformation was realized by utilizing a new type of enol activation catalysis and affords different cyclic ketones bearing α-quaternary stereocenters in good to excellent yields and with high enantioselectivity. Subsequent McMurry coupling and Saegusa-Ito oxidation furnished the enantiopure target odorants, one enantiomer of which indeed possesses the typical olfactory aspects of Cashmeran.
authors.affiliation: Givaudan Schweiz AG, Fragrance Research, Überlandstrasse 138, 8600 Dübendorf (Switzerland) http://www.givaudan.com.
authors.forename: Irene
authors.initials: I
authors.lastname: Felker
authors.forename: Gabriele
authors.initials: G
authors.lastname: Pupo
authors.forename: Philip
authors.initials: P
authors.lastname: Kraft
authors.forename: Benjamin
authors.initials: B
authors.lastname: List
keywords: Brønsted acid catalysis; Michael addition; enol catalysis; fragrances; structure-activity relationships