Synthesis of chiral methyl-branched linear pheromones starting from (+)-aromadendrene. Part 7

From Labdanes to Drimanes. Degradation of the Side Chain of Dihydrozamoranic Acid.

“…Treatment of 9 under Wacker conditions [15] with CuCl/PdCl 2 /O 2 , lead to ketone 10 in 80% yield. Baeyer-Villiger oxidation [16] of 10 with m-CPBA gives 11, a 1:2 mixture of α and β epoxides, in 95% yield. This compound shows a degradation of the side chain by two carbons.…”

Research Progress on the Syntheses of Chiral Methyl-Branched Aliphatic Hydrocarbons Insect Pheromones

“…图 1 单手性甲基脂肪烃类昆虫信息素 Figure 1 Single chiral methyl-branched hydrocarbon insect pheromones 1.1 手性源法 手性源法是以具有光学活性的化合物为起始原料, 经过一系列化学反应制备目标化合物的单一对映体的 方法 [26][27] . 在单手性甲基昆虫信息素的合成研究中, 常 用的手性源试剂有(R)-与(S)-香茅醇 [28] 、(R)-与(S)-香茅 醛 [29] 、(R)-香茅酸 [30] 、(＋)-香橙烯 [31] 、(-)-薄荷醇 [32] 、 (R)-与(S)-2-甲基-3-羟基丙酸甲酯 [33][34] 、(-)-薄荷酮内 酯 [35] 、(R)-3-甲基-4-丁内酯 [36] 、(R)-与(S)-2-甲基丁基 溴 [37] 、溴化三苯基(R)-(2-甲基-3-羟基丙基)鏻 [38] 等.…”

Chiral methyl-branched pheromones

“…The larvae are defoliators, and many species cause serious agricultural and forestry damage. The pheromones are propionates or acetates of secondary alcohols with one, two, or three methyl branch(es) in a C 11 -C 15 chain (50)(51)(52)(53)(54)(55)(56)(57)(58)(59). Compounds of another type have been scarcely reported as pheromones of the sawy in the family Diprionidae.…”

“…As another natural chiral source, aromadendrene (S4) was used for the monomethyl hydrocarbon (11) and 2-ketone (74). 55 A chiral methylbranched C 10 -chain intermediate was prepared from (+)-S4 in 1b. Citronellic acid (S1c) derived from isopulegol or pulegone D8,Me14-16:Ald (40), 125,126 Me8-10:2-OPr (47), 145 nine steps that included Baeyer-Villiger oxidation and Grob fragmentation as the key reactions.…”