Stereoselective synthesis of 10,14-dimethyloctadec-1-ene, 5,9-dimethyloctadecane, and 5,9-dimethylheptadecane, the sex pheromones of female apple leafminer

Enantiospecific synthesis and filed evaluation of four stereoisomers of 10,14-dimethyloctadec-1-ene, a sex pheromone component secreted by female moths of the apple leafminer

“…Purification of the crude product with a AgNO 3 -SiO 2 column gave the desired terminal alkene (10S,14S)-1 in an 86% yield from (S)-9. The following chemical data of (10S,14S)-1 were almost identical to those published with regard to previous syntheses, 7,8,11,12) indicating that racemization did not occur after the coupling; and (R)-9, and (10R,14R)-1 (½a 23 D = −2.0, c = 1.5, CHCl 3 ) from (R)-7 and (R)-9. While the 1 H NMR spectra of the four stereoisomers were identical, the diastereomers showed small but discernible differences in chemical shifts for some 13 C-11, 13), 114.09 (C-1), 139.28 (C-2) ppm.…”

“…10) Subsequently, other synthetic routes applying Cu-phosphoramiditecatalyzed asymmetric addition of Me 2 Zn 11) and Evans's stereo selective alkylation 12) have been reported. Recently, we achieved a simple method of constructing a chiral methyl-branched skeleton by an S N 2 reaction with a tosylate of 2-alkanol, which was derived from commercialized (R)-and (S)-propylene oxide (2) with a high enantiomeric excess (ee).…”

Syntheses of (R)‐ and (S)‐3‐Methylheptanoic Acids

“…After being neutrilized with saturated NaHCO 3 , washed with brine, the organic layer was dried over Na 2 SO 4 and concentrated in vacuo to afford 12 (85 mg, 0.73 mmol, 83%) as colorless oil. [3] …”

Synthesis of stereopure acyclic 1,5-dimethylalkane chirons: building blocks of highly methyl-branched natural products

“…The chiral 1,5-dimethylalkane subunit is ubiquitous among many biologically active natural products (Figure 1), such as vitamins, 1,2 phytol, 3 insect pheromones [4][5][6][7][8][9][10][11][12] , marine natural M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT products, 13,14 archaeal lipids, [15][16][17][18] and the bacterial membrane lipids (β-D-mannosyl phosphomycoketides). 19,20 Total synthesis of these methyl-branched natural products has been an interesting and active subject for several decades due to their structural determinations and their increasing biological and biomedical applications.…”

“…We also prepared four stereopure 1,5-dimethylalkane C 10 chirons ( Figure 2C) from (S)-1 and/or (R)-1. To further evaluate the synthetic value of these chirons in natural product synthesis, we prepared the vitamin E C 14 (3R, 7R, 11R) VII: 15,16 Archaeol lipid, a lipid isolated from Methanobacterium thermoautotrophicum III: [4][5][6][7][8] Insect pheromone…”