On the Crossroad of Dienone Musks and Cassyrane: Synthesis and Olfactory Properties of New High-Impact Orris Odorants

Kraft, Philip; Ahlin, Joachim S. E.; Büchel, Michelle; Sutter, Pascal

doi:10.1055/s-0032-1317033

Cited by 11 publications

(8 citation statements)

References 20 publications

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“…These ynones were subsequently transformed into pyrazole potassium trifluoroborates by reaction with hydrazines (see section 3.1.3.1.3), which can be further submitted to Pd-catalyzed cross-coupling reactions. For the synthesis of orris odorants, ynones 20 29 have been used as synthetic intermediates which were prepared by oxidation of the precursors, propargylic alcohols with MnO 2 in 78−90% yields (Figure 1). Cossy and co-workers prepared the enynone 21 19 by MnO 2 oxidation of the corresponding alcohol in 83% yield (Figure 1).…”

Section: From Propargylic Alcoholsmentioning

confidence: 99%

Conjugated Ynones in Organic Synthesis

2019

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This review article will consider the preparation and application of ynones in synthetic organic chemistry. Concerning the preparation of these bifunctional compounds, several methodologies starting from propargyl alcohols, acyl derivatives, both by using alkynylmetal reagents or by transition metal (mainly palladium and copper) catalyzed alkynylations, carbon monoxide (carbonylation of terminal alkynes and alkenes), and other substrates will be discussed. The reactivity and synthetic applications of ynones will be focused on conjugate additions with boron-, carbon-, nitrogen-, oxygen-, and other heteroatom-containing nucleophiles, as well as radicals. Then, cycloaddition processes will include [2 + 2] cycloadditions, [3 + 2] 1,3-dipolar cycloadditions (with azides, nitrones, azomethine imines and ylides, nitrile oxides, diazo compounds, and other dipoles), and [4 + 2] cycloadditions (mainly Diels–Alder-type reactions). The reduction of the triple bond, addition to the carbonyl group (using carbon- and heteronucleophiles and reductions), and other not so commonly used processes (such as aldol reactions, cyclizations, and isomerizations) will be considered at the end.

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Section: From Propargylic Alcoholsmentioning

confidence: 99%

Conjugated Ynones in Organic Synthesis

2019

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“…This exact transformation had been previously reported by others using different reaction conditions [Pd(PPh 3 ) 4 /ZnCl 2 /Ph 2 SiH 2 2 or Hantzsch ester/SiO 2 3 ] that were found not to be generally selective across a range of conjugated dienone substrates; we therefore thought that the selective conversion of 2a into 3a might simply be due to steric interference by the methyl groups. To our knowl-edge, the only reported general methods for the selective ,-reduction of conjugated polyunsaturated ketones involve the use of catecholborane, 4 Stryker's reagent, 5 or a catalytic InCl 3 /NaBH 4 reaction system. 6 Additionally, a B(C 6 F 5 ) 3 /poly(methylhydrosiloxane) reaction system that might be highly selective has been reported, but it was applied to only a single polyunsaturated ketone substrate and a related ester-nitrile substrate.…”

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confidence: 99%

Triphenylphosphine Oxide-Catalyzed Selective α,β-Reduction of Conjugated Polyunsaturated Ketones

Xia¹,

Lao²,

Toy

2019

Synlett

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The scope of the triphenylphosphine oxide-catalyzed reduction of conjugated polyunsaturated ketones using trichlorosilane as the reducing reagent has been examined. In all cases studied, the α,β-C=C double bond was selectively reduced to a C–C single bond while all other reducible functional groups remained unchanged. This reaction was applied to a large variety of conjugated dienones, a trienone, and a tetraenone. Additionally, a tandem one-pot Wittig/conjugate-reduction reaction sequence was developed to produce γ,δ-unsaturated ketones directly from simple building blocks. In these reactions the byproduct of the Wittig reaction served as the catalyst for the reduction reaction. This strategy was then used in the synthesis of naturally occurring moth pheromones to demonstrate its utility in the context of natural-product synthesis.

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“…First, Stryker's method11 was used for the selective reduction of the α,β‐double bond of (3 E ,5 E )‐5‐ tert ‐butyl‐7‐methylocta‐3,5‐dien‐2‐one ( 2 ) using the Osborn complex, a hexameric copper hydride ligated with triphenylphosphine [(Ph 3 P)CuH] 6 , and the (5 E )‐configured monohydrogenated isopropyl derivative (i.e., 9 ) was obtained in 73 % yield. This compound had previously been prepared in 40 % yield by catecholborane reduction of 2 ,12,13 and it has a relatively weak (th = 199 ng L –1 air) green‐piney musk odor of fatty‐waxy tonality with slightly animalic aspects. Attempts to reduce the α,β‐double bond of tert ‐butyl‐substituted dienone musk 3 with Stryker's reagent11 were, however, unsuccessful, and therefore the procedure of Evans and Fu13 using catecholborane was used instead.…”

Section: Resultsmentioning

confidence: 99%

“…Fully hydrogenated ketones 11 12 and 14 were prepared by standard catalytic hydrogenation of dienones 2 and 3 in the presence of palladium on charcoal in 94 and 80 % yields, respectively. In both of 11 and 14 , the woody character is pronounced.…”

Section: Resultsmentioning

confidence: 99%

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On the Dienone Motif of Musks: Synthesis and Olfactory Properties of Partially and Fully Hydrogenated Dienone Musks

Kraft¹,

Jordi²,

Denizot³

et al. 2013

Eur J Org Chem

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Minimum‐energy calculations and the conformation of the (11Z)‐retinylidium moiety in bovine rhodopsin called into doubt that the function of the dienone motif of a new class of musk odorants 1–6 was to stiffen and planarize the compounds. To investigate the function and importance of these double bonds, the three most potent representatives of the family of dienone musks were partially and fully hydrogenated, and the products were evaluated for their olfactory properties. Stryker's method using the Osborn complex and the procedure of Evans and Fu utilizing catecholborane were used for the reduction of the α,β‐double bonds, palladium on CaCO3 was used for the reduction of the γ,δ‐double bonds, and palladium on charcoal was used for the complete hydrogenation of the dienone systems in 2–4. trans‐Configured cyclopentyl derivatives 23 and 24 were synthesized from 4,4‐dimethylcyclohex‐2‐en‐1‐one by Weitz–Scheffer epoxidation, sodium borohydride reduction, rearrangement to the corresponding carbaldehyde using lithium bromide in toluene/HMPT, cuprate alkylation with the tert‐butyl Gilman reagent, aldol condensation with acetone, and optional hydrogenation with palladium on charcoal. Of the synthesized derivatives, only the γ,δ‐unsaturated enones (i.e., 9, 12, and 15) have a typical musk odor, indicating that the γ,δ‐double bond interacts electronically with the musk receptor(s). As enones 9, 12, and 15 are, however, less intense than the parent compounds (i.e., 2–4), the α,β‐double bond seems to intensify the odor strength due to conformational effects. Conformational effects also seem to favor compounds with an endocyclic γ,δ‐double bond over acyclic dienone systems for their intensity and musk character. In acyclic compounds 10 and 13, the α,β‐double bond introduces violet–orris facets.

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On the Crossroad of Dienone Musks and Cassyrane: Synthesis and Olfactory Properties of New High-Impact Orris Odorants

Cited by 11 publications

References 20 publications

Conjugated Ynones in Organic Synthesis

Conjugated Ynones in Organic Synthesis

Triphenylphosphine Oxide-Catalyzed Selective α,β-Reduction of Conjugated Polyunsaturated Ketones

On the Dienone Motif of Musks: Synthesis and Olfactory Properties of Partially and Fully Hydrogenated Dienone Musks

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