Citronellal as key compound in organic synthesis

Selective Monoterpene-like Cyclization Reactions Achieved by Water Exclusion from Reactive Intermediates in a Supramolecular Catalyst

“…32 Formation of 3a as the major product is also important, as this compound is a direct industrial precursor to menthol, a fine chemical of multi-ton yearly production. 18 The synthesis of 3a from 2 is conventionally accomplished using organic solvents and Lewis acids, where dehydration and dimerization products are often observed. 33,34 In contrast, catalysis by 1 provides an environmentally benign method to afford products of synthetic and economic utility without the byproducts often observed from Lewis acid treatment.…”

“…The monoterpene (±)-citronellal (2) has been shown to cyclize in the presence of Brønsted acids and is a relevant industrial intermediate in the manufacture of menthol. 18 We hypothesized that 1 would stabilize the conjugate acid of encapsulated 2, driving protonation at the aldehyde oxygen and subsequent cyclization, the latter process being accelerated by the constrictive interior of 1. Herein we report our studies of a catalytic cyclization of 2 and two homologues (6a, 7a) in a water-soluble supramolecular assembly at moderate temperatures and physiological pH.…”

Bioassay-guided evaluation of central nervous system effects of citronellal in rodents

“…Therefore, citronellal (CT) (1) is a monoterpene, predominantly formed by the secondary metabolism of plants. It is typically isolated as a non-racemic mixture of its R and S enantiomers by steam distillation or solvent extraction from the oils of Corymbia citriodora Hill and Johnson (former Eucalyptus citriodora Hook) Cymbopogon nardus and C. winterianus (Lenardão et al, 2007). Recently, in a preliminary behavioral screening realized with the essential oil of the C. winterianus, our group demonstrates CNS depressant and anticonvulsant activities in rodents (QuintansJúnior et al, 2008b).…”

Synthesis of All the Stereoisomers of 6-Methyl-2-octadecanone, 14-Methyl-2-octadecanone, and 6,14-Dimethyl-2-octadecanone, Sex Pheromone Components of theLyclene dharma dharmaMoth, from the Enantiomers of Citronellal

“…We adopted the procedure previously reported for the synthesis of (R)-8 7,8) with slight modifications to improve the yield in the conversion of 6 to 8. Accordingly, (S)-citronellal was converted to (S)-citronellyl iodide (6) 6-methyl-2-octadecanone (1) (50 ng / female) 14-methyl-2-octadecanone (2) 6,14-dimethyl-2-octadecanone (3) trimethylsilylacetylenide with 6 was best carried out by employing 1.5 eq. of the acetylenide in THF/HMPA (5:1) and then heating the reaction mixture under reflux for 2 h to give (S)-7 in an 80% yield.…”

“…5) In order to secure additional amounts of the stereoisomers of 1, 2 and 3, we planned their alternative synthesis based on classical carbon-carbon bond formation reactions employing the commercially available enantiomers of citronellal, whose use in enantioselective synthesis has recently been reviewed. 6) This paper describes our second synthesis of all the possible stereoisomers of 1, 2 and 3.…”