An Alternative Route for the Synthesis of (E)-(+)-5(S)-Methylhept-2-en-4-one (Filbertone)

Abstract

Foi estudada uma metodologia alternativa para a obtenção da (+)-Filbertone (1), um aromatizante natural isolado de avelãs. Utilizou-se o álcool comercial (-)-2(S)-metilbutan-1-ol (2) como material de partida, sendo a síntese realizada em quatro etapas com rendimento global de 42%. A rotação óptica e pureza enantiomérica do produto final foram determinados.We are reporting an alternative methodology to prepare (+)-Filbertone (1), a natural flavor isolated from hazelnut extracts. Commercially available (-)-2(S)-methylbutan-1-ol (2) was used as starting material and the synthesis was carried out in four steps with an overall yield of 42%. The optical rotation and the enantiomeric purity of the final compound were determined.

Filbertone: A Review

“…An alternative but similar approach 22 exploited allylation of known aldehyde 27 with an organozinc nucleophile to provide a diastereomeric mixture of homoallylic alcohols 11A. This was oxidized to afford ketone 12A, which was finally isomerized to the desired target.…”

Alarm pheromone system of stink bug Piezodorus guildinii (Heteroptera: Pentatomidae)

“…The monoprotected alcohol 9 was obtained after protection of the diol 8 with DHP in 60 % yield 10 . Oxidation of 9 with PCC in methylene chloride afforded the aldehyde 10 in 80% yield 11 . Coupling of this compound with ethylmagnesium bromide 12 yielded the alcohol 11 (65 %) which was deprotected to give diol 12 (88%) by treatment with pTSA in methanol 10 .…”

Scalable Preparation of Enantioenriched (S)-5-methylhept-2-en-4-one. Synthesis and Aroma Properties of Achiral Analogues Thereof

“…To date, only three enantioselective syntheses of (S)-5-methylhept-2-en-4-one 1 are known [2][3][4], and all employ enantiomerically pure (S)-2-methylbutanol as substrate, with 40% overall yield (75% and 92% ee). However, these strategies rely on synthetic methods either requiring strictly anhydrous conditions (organolithium addition, hydride reduction) or use/generate toxic reagents/waste (chromium salts), and thus, severely limiting their scaling potential.…”

“…The reaction was quenched with saturated aqueous NH 4 Cl solution, diluted with water and extracted with diethyl ether. Combined organic extracts were dried over mgSO4 and concentrated in vacuo (34 • C, 650 → 250 mbar). Crude product was purified by bulb-to-bulb vacuum distillation to furnish a corresponding allyl alcohol 13-16.…”