桃潜蛾性信息素的合成研究

(-)-莰烷磺内酰胺手性助剂与巴豆酸酰氯作用生成N-反式丁烯酰基衍生物(4),进而与n-C~4H~9MgBr进行Michael加成反应,发现在CuBr.Me~2S存在下,产物以S构型为主,且化学产率明显提高。经六步合成了桃潜蛾性信息素(S)-14-甲基-1-十八碳烯(1)及其对映异构体(R)-1。     

Efficient synthesis of (R)- and (S)-3-octanol, (R)-2-dodecanol, (R)-2-methyl-4-heptanol and (R)-2-methyl-4-octanol: the pheromones of Myrmica scabrinodis, Crematogaster castanea, C. liengmei, C. auberti and Metamasius hemipterus

A simple and efficient synthesis of optically active insect pheromones, such as (R)- and (S)-3-octanol, (R)-2-dodecanol, (R)-2-methyl-4-heptanol and (R)-2-methyl-4-octanol starting from non-racemic β-hydroxy sulfides has been established.     

Stereoselective synthesis of C1-C9 and C9-C17 fragments of (+)-13-deoxytedanolide

An efficient and highly stereoselective asymmetric synthesis of C1-C9 and C9-C17 fragments of (+)-13-deoxytedanolide have been achieved. Utilization of desymmetrization technique to prepare the triol with five stereogenic centers, regioselective Sharpless asymmetric dihydroxylation, Evans' aldol reaction, chiral methylation, and Wittig olefination are highlights of the synthesis.     

Radical mediated stereoselective synthesis of meso-7,11-dimethylheptadecane, a female sex pheromone component of the spring hemlock looper and the pitch pine looper

meso-7,11-Dimethylheptadecane, a female sex pheromone component of the spring hemlock looper and the pitch pine looper, was synthesized from ethyl 2-(bromomethyl)propenoate in nine steps and 14% overall yield. The key step in the synthesis is the highly diastereoselective chelation-controlled radical reaction of diethyl 4-benzyloxy-2,6-dimethyleneheptanedioate with pentyl iodide performed in the presence of 6 equiv of MgBr₂·OEt₂.     

Design, chemical synthesis, and biological evaluation of novel triazolyl analogues of taranabant (MK-0364), a cannabinoid-1 receptor inverse agonist

Being obese has various health problems that are related to type 2 diabetes mellitus, cardiovascular disease, hypertension, hyperlipidemia, and fibrinolytic abnormalities. Merck's taranabant (MK-0364), a CB1R inverse agonist, is currently in Phase 3 clinical trials, and is being actively pursued by Merck toward obesity market. Merck intends to file for FDA approval of taranabant in 2008. In order to increase solubility and potency of taranabant, or even possibly improve safety, novel triazole analogues of taranabant have been designed and synthesized. We introduced a pivotal asymmetric center via the Evans chiral auxiliary methodology and set up 1,2,4-triazole via substitution of α-bromoketone. Subsequently, diastereoselective reduction was accomplished to install adjacent essential asymmetric center. This method allowed us to prepare readily sub-gram scale of the target compounds in a convenient way. The synthesized analogues were subjected to biological evaluation involving cannabinoid CB1 receptor binding affinity. While the parent taranabant bears highly potent binding affinity to cannabinoid CB1 receptor, neither of the analog structures improved CB1 receptor binding affinities.     

(6Z,9Z,12Z)-6,9,12-Octadecatriene and (3Z,6Z,9Z,12Z)-3,6,9,12-icosatetraene, the novel sex pheromones produced by emerald moths

(6Z,9Z,12Z)-6,9,12-Octadecatriene and (3Z,6Z,9Z,12Z)-3,6,9,12-icosatetraene, hydrocarbons unsaturated more highly than usual lepidopteran Type II pheromones, were identified from geometrid females of Hemithea tritonaria and Thalassodes immissaria intaminata, respectively. The triene was synthesized by a double Wittig reaction between hexanal and an ylide derived from (Z)-1,6-diiodo-3-hexene, and the tetraene was synthesized by a coupling between (Z)-3-undecenal and an ylide derived from (3Z,6Z)-1-iodo-3,6-nonadiene. Each synthetic compound attracted males of the corresponding emerald moths in a field.     

Stereoselective synthesis of (2S,3S,7S)-3,7-dimethylpentadecan-2-ol and its propionate,the sex pheromones of pine sawflies

The stereoselective synthesis of (2S,3S,7S)-3,7-dimethylpentadecan-2-ol (diprionol) and its propionate, the sex pheromones of pine sawflies (Neodiprion sp. and other), in high enantiomeric purity was achieved from (1R,3S)-2,2-dichloro-3-methylcyclopropanecarboxylic acid. The carbon skeleton of diprionol was formed via copper-catalyzed cross-coupling reactions and diastereoselective methylation of the intermediate chiral α-methylbranched aldehyde with MeTi(Oi-Pr)₃ in the presence of [(R,R)-TADDOL]Ti(Oi-Pr)₂. The latter transformation leads to a syn-adduct with high stereoselectivity, which depends on the presence and configuration of the α-stereogenic center in the aldehyde. The diastereomeric purity of (2S,3S,7S)-diprionol can be substantially increased via crystallization of its 3,5-dinitrobenzoate.     

Catalytic and asymmetric Friedel-Crafts alkylation of indoles with nitroacrylates. Application to the synthesis of tryptophan analogues

An asymmetric Friedel-Crafts alkylation of indoles with nitroacrylates catalyzed by chiral (4R,5S)-DiPh-BOX (L1)-Cu(OTf)₂ complex (10 mol %) has been developed. The reactions provide tryptophan nitro-precursors in moderate diastereoselectivities (anti/syn up to 72:28) and good to excellent enantioselectivities (up to 99% ee). The alkylation products could be easily reduced to optically active tryptophan analogues with Zn/H⁺.     

Stereoselective synthesis of (2S,3S,7S)-3,7-dimethylpentadec-2-yl acetate and propionate, the sex pheromones of pine sawflies

The stereoselective synthesis of (2S,3S,7S)-3,7-dimethylpentadec-2-yl acetate (2) and propionate (3) was accomplished by utilizing the cheap and easily available chiron (R)-4-methyl-δ-valerolactone (4). The key steps were chelation-controlled addition of Gilmann reagent to chiral β-alkoxy aldehyde 12 and the Cu(I)-catalyzed coupling of Grignard reagent with bromoester 5 in the presence of NMP.     

Syntheses of (4E,6E, 11Z)-4,6,11-hexadecatrienyl acetate and (4E, 6E, 11Z)-4,6,11-hexadecatrienal, female sex pheromones of eri-silkworm, Samia cynthia ricini (Lepidoptera: Saturniidae)

Syntheses of (4E,6E,11Z)-4,6,11-hexadecatrienyl acetate (1) and (4E,6E, 11Z)-4, 6,11-hexadecatrienal (2), female sex pheromones of eri-silkworm,Samia cynthia ricini have been achieved through Claisen ortho ester rearrangement of (6).     

有机硅试剂在昆虫性信息素合成中的应用: 桃小食心虫性息素-顺-7-二十烯酮-11和顺-7-十九烯酮-11的全合成

本文报导应用有机硅试剂合成顺式烯烃-桃小食心虫性信息素的结果, 这条合成路线原料易得, 产率高和具有较好的立体选择性。     

Design and synthesis of a new polymer-supported Evans-type oxazolidinone: an efficient chiral auxiliary in the solid-phase asymmetric alkylation reactions

Wang resin-supported Evans' chiral auxiliary (23) was designed based on a novel polymer-anchoring strategy, which utilizes the 5-position of the oxazolidinone ring, and its new synthetic route applicable to multi-gram preparation in just a day was developed. Solid-phase Evans' asymmetric alkylation on 23-derived N-acylimide resin and following lithium hydroperoxide-mediated chemoselective hydrolysis afforded the corresponding α-branched carboxylic acids in desired high stereoselectivities (up to 97% ee) and moderate to good overall yield (up to 70%, for 3 steps), which were comparable to those of the conventional solution-phase methods. Furthermore, recovery and recycling of the polymer-supported chiral auxiliary were successfully achieved without decreasing the stereoselectivity of the product. Therefore, this is the first successful example that the solid-phase Evans' asymmetric enolate-alkylation was efficiently performed on the solid-support, and it is concluded that the connection to the solid-support via the 5-position of the oxazolidinone ring is an ideal strategy in the solid-phase Evans' chiral auxiliary.     

Stereoselective addition of Grignard reagents to sulfinimines derived from tartrate diol (threitol): Generation of chiral building blocks for the collective total synthesis of lentiginosine,conhydrine and methyldihydropalustramate

A systematic investigation of the addition of Grignard reagents to sulfinimines derived from tartaric acid diol was undertaken. It was observed that the chirality of the inherent tartrate moiety influences the diastereoselectivity of the resultant sulfinamides formed in the reaction. The formed products serve as excellent building blocks for the synthesis of natural products. This has been demonstrated in the collective total synthesis of lentiginosine, (+)-α-conhydrine and methyldihydropalustramate.     

Stereoselective synthesis of the densely functionalized C1-C9 fragment of amphidinolides C and F

The synthesis of the C1-C9 subunit of amphidinolides C and F is described. Key steps include tandem Sharpless asymmetric dihydroxylation-S_N2 cyclization reaction, Lewis acid-mediated epoxide opening, Wittig reaction, and Wacker oxidation.     

Pheromones of insects and their analogs. V. A new approach to the synthesis of the sex pheromones of insects of the orderLepidoptera which is based on the selective ozonolysis of 1-methylcycloocta-1Z,5Z-diene

A new synthesis of 1-acetoxyalk-Z-enes (sex pheromones of insects of the orderLepidoptera) has been developed which is based on the selective ozonolysis of 1-methylcycloocta-1Z-5Z-diene — a cooligomer of isoprene and butadiene.     

Pheromones of insects and their analogs. XXVIII. Practical synthesis of tetradeca-9Z,12E-dien-1-yl acetate — A component of the sex pheromones of insects of the order lepidoptera

Tetradeca-9Z,12E-dien-l-yl acetate, a sex pheromone of the Indian meal mothPlodia interpunctella has been synthesized from the readily available product of the hydrodimerization of butadiene — octa-1,7-diene.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 276–279, March–April, 1991.     

Insect pheromones and their analogues XLVIII. A convenient synthesis of the 10E,12Z- and 10E,12E- isomers of hexadecadien-1-ol and of hexadeca-10E,12Z-dienal — Components of the sex pheromone of the silkworm moth

The 10E,12Z- and 10E,12E- isomers of hexadecadien-1-ol and of hexadeca-10E,12Z-dienal — components of the sex pheromone of the silkworm mothBombyx mori — have been synthesized from the readily available octa-2E,7-dien-1-ol.     

Studies towards the total synthesis of cruentaren A and B: Stereoselective synthesis of fragments C1-C11, C12-C22 and C23-C28

A convergent and stereoselective approach for the synthesis of C1-C11, C12-C22, and C23-C28 fragments of cytotoxic natural products cruentaren A and B are accomplished. Highlights of the strategy include a Sharpless epoxidation followed by a regioselective opening of epoxide to generate anti and syn-stereochemistry at C9-C10 and C15-C16, an Alder-Rickert reaction between a 1,5-dimethoxy-1,4-cyclohexadiene and dienophile to construct the aromatic ring, and a lithium-mediated aldol reaction to install the C17-C18 anti-stereochemistry. The synthesis of C1-C11 and C12-C22 fragments proceed with a longest linear sequence of 10 and 17 steps from commercially available 2-butyne-1,4-diol and cis-2-butene-1,4-diol respectively.     

A new and efficient synthesis of (3E,8Z,11Z)-tetradeca-3,8,11-trienyl acetate,the major sex pheromone component of the tomato leafminer Tuta absoluta

An efficient synthesis of (3E,8Z,11Z)-tetradeca-3,8,11-trienyl acetate, the major sex pheromone component of the tomato leafminer moth, Tuta absoluta, was accomplished. The synthesis started with but-3-yn-1-ol and gave an overall yield of 41%.