Stereospecific Synthesis of Two Isomers of (4,8) - Dimethyldecanal: The Aggregation Pheromone of Tribolium spp

Abstract

Uma síntese estereoespecífica para dois estereoisômeros, (4R, 8S) e (4S, 8S), do 4,8-dimetildecanal (1), entre os quatro possíveis, é descrita em apenas três etapas. A etapa chave emprega a reação de acoplamento dos tosilatos (3) e (3a), obtidos do (R)-e (S)-citronelol, com o reagente de Grignard preparado a partir do (S)-(+)-1-bromo-2-metilbutano (4) comercial.A straightforward stereospecific synthesis of two stereoisomers, (4R, 8S) and (4S, 8S), of 4,8-dimethyldecanal (1), out of four possible isomers, is described. The key step employs the coupling reaction of tosylates (3) and (3a), which are obtained from (R)-and (S)-citronellol, with the chiral Grignard reagent prepared from comercial (S)-(+)-1-bromo-2-methylbutane (4).

Male-Produced Sex Pheromone of the Cerambycid Beetle Hedypathes betulinus: Chemical Identification and Biological Activity

“…3b) showed a molecular ion of m/z 196, a base peak at m/z 41, and other fragments at m/z 69 (90%) and 153 (34%), suggesting that B may be related to geranylacetone with hydrogenation at the carbon 5, or the corresponding alcohol, geranylacetol. Reduction of compound A with LiAlH 4 (Zarbin et al, 1998) yielded an alcohol with the same retention time and mass spectrum as compound B, confirming its chemical structure as (E)-6,10-dimethyl-5,9-undecadien-2-ol. In a previous study, this alcohol was identified as the primary component of the male-produced sex pheromone of the longhorn beetles, Tetropium fuscum and Tetropium cinnamopterum, members of the Spondylidinae subfamily, and was named fuscumol (Silk et al, 2007).…”

Total synthesis of (6R,12R)‐6,12‐dimethylpentadecan‐2‐one, the sex pheromone of Diabrotica balteata LeConte

“…The reaction of chiral bromide 19 with Mg afforded (R)-(4-methylheptyl)magnesium bromide, followed by LiCuCl 4 catalyzed coupling with chiral tosylate 9 generated (6R,12R)-2,6,12-trimethylpentadec-1-ene (20) in 90% yield. 37 The oxidative cleavage of olefin 20 with NaIO 4 / RuCl 3 afforded (6R,12R)-6,12-dimethylpentadecan-2-one (1). 38 Furthermore, its structure was characterized with 1 H NMR, 13 C NMR, specific rotation, and HRMS, which were identical to the literature data.…”

“…With two chiral fragments 9 and 19 in hand, we prepared the target sex pheromone 1 (Scheme 3). The reaction of chiral bromide 19 with Mg afforded ( R )‐(4‐methylheptyl)magnesium bromide, followed by LiCuCl 4 catalyzed coupling with chiral tosylate 9 generated (6 R ,12 R )‐2,6,12‐trimethylpentadec‐1‐ene ( 20 ) in 90% yield 37 . The oxidative cleavage of olefin 20 with NaIO 4 /RuCl 3 afforded (6 R ,12 R )‐6,12‐dimethylpentadecan‐2‐one ( 1 ) 38 .…”

Ultrasound Assisted Synthesis of 5,9-Dimethylpentadecane and 5,9-Dimethylhexadecane – the Sex Pheromones of Leucoptera coffeella

“…The aldehydes 6a and 6b can be prepared from the alkenes 5a and 5b by ozonolysis [12]. In this work, the alkenes 5a and 5b were oxidized by perphthalic acid, then periodic acid [13], to give 6a and 6b, in of 81-82% yields, respectively, The alcohols 7a and 7b were easily prepared from the aldehydes 6a and 6b in yields of 96-97% by reduction of the latter with sodium borohydride in methanol for 15 minutes.…”