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Leukotriene B 4 1 was prepared from two chiral synthons 8 and 14 . The chiral secondary alcohols of 8 and 14 were constructed by BINOL/Ti(O i Pr) 4 catalyzed enantioselective alkynylzinc addition to aldehydes. [ABSTRACT FROM AUTHOR]

An efficient synthesis of panaxytriol and its seven stereoisomers was achieved, and four unnatural diastereomers of 2a were prepared. The key steps involved the opening of vicinal hydroxy epoxides, the stereospecific opening of the epoxides with perchloric acid, and the Cadiot–Chodkiewicz cross-coupling of chiral terminal alkynes with bromoalkynes. Preliminary antitumor activity investigations indicated that some synthetic panaxytriols exhibited promising cytotoxic activity against three human cancer cell lines. [ABSTRACT FROM AUTHOR]

Abstract: A new series of amino alcohols with a chiral cyclopropane backbone have been developed and used in the catalytic asymmetric diethylzinc addition and phenyl transfer to various types of aldehydes. These cyclopropane-based chiral amino alcohols show high enantioselectivity in the addition of organozincs to aromatic and aliphatic aldehydes. For diethylzinc addition to aromatic and aliphatic aldehydes, up to 97% ee and 93% ee are obtained, respectively. For the phenyl transfer to aromatic aldehydes, the best enantioselectivity was 89% ee. [Copyright &y& Elsevier]

An efficient total synthesis of natural panaxydol 1a and its seven stereoisomers 1b – h was accomplished; four diastereomers of the natural form were prepared for the first time. Our strategy involves the Cadiot-Chodkiewicz cross-coupling reaction of chiral terminal alkynes with bromoalkynes, the asymmetric alkynylation of aldehydes, and the enantioselective Sharpless epoxidation of allylic alcohols. Preliminary in vitro cytotoxicity evaluation indicated that some synthetic panaxydols possess anticancer activities, and (3 S ,9 R ,10 S )-panaxydol 1e showed a particularly promising cytotoxic effect. [ABSTRACT FROM AUTHOR]

The first asymmetric catalytic synthesis of (−)-oudemanisin A 1a and its diastereomer 1b has been achieved. The key steps of our strategy involved the asymmetric alkynylation of an unsaturated aliphatic aldehyde catalyzed by Trost’s ProPhenol ligand, chemoselective oxidation of the olefinic diol, base-induced ring opening of the lactone, and acylation–alkylation of the ester. [ABSTRACT FROM AUTHOR]

The first enantioselective synthesis of (2 R ,13 R ,8 Z )-2,13-diacetoxy-8-heptadecene 1 , the major component of the sex pheromone of the pear leaf midge, Dasineura pyri , has been achieved. The key steps include the ( R , R )-BINOL/Ti(O i Pr) 4 catalyzed alkynylzinc addition to an unsaturated aldehyde, the ring-opening of the chiral epoxide with a Grignard reagent, and the partial reduction of an acetylenic diol ester to a ( Z )-olefinic diol ester with hydrogen and P2-Ni. [ABSTRACT FROM AUTHOR]

The first total syntheses of 9-epoxyfalcarindiol 1a and its diastereomer 1b have been achieved. Central to our approach were the Zn-cyclopropane-based amino alcohol catalyzed enantioselective alkynylation of acrolein, the diastereoselective addition of a diynic ester to an epoxy aldehyde, and the asymmetric Sharpless epoxidation of allylic alcohol catalyzed with L -(+) - diethyl tartrate and Ti(O i Pr) 4 . [ABSTRACT FROM AUTHOR]

[Display omitted] The western hemlock looper is an economically important defoliator of coniferous trees. Its sex pheromone has been synthesized in 36–50% total yield using the enantiomers of 2-methyloxiraneoxide as chiral sources. The key steps of this strategy involved CuI catalyzed ring-opening of chiral 2-methyloxiraneoxide, stereospecific inversion of secondary tosylate and Wittig coupling of the aldehyde with chiral phosphonium salt. The synthetic pheromones would be used to monitor and control this pest. [ABSTRACT FROM AUTHOR]

• A novel cerium-based nanomaterial is prepared by a facile approach. • The cerium-based nanomaterial exhibits superior oxidase-like activity. • A colorimetric sensor is developed based on the cerium-based nanomaterial for OPs with high sensitivity and selectivity. • The sensor array is low cost and simple in preparation and operation. Cerium, as a lanthanide, has attracted considerable interest because of its excellent catalytic activity. Here, we propose a novel cerium-based coordination polymer nanoparticles named DPA–Ce–GMP, which have excellent oxidase-mimicking properties. Furthermore, a colorimetric probe that can act as an inhibitor to suppress the activity of acetylcholinesterase (AChE) was developed for detecting organophosphorus pesticides (OPs). DPA–Ce–GMP catalyzes colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue color, and AChE catalyzes acetylthiocholine to produce thiocholine (TCh), which can weaken DPA–Ce–GMP-catalyzed TMB. After the addition of OPs, the enzymatic activity of AChE was inhibited to produce less amount of TCh, resulting in more DPA–Ce–GMP-catalyst oxidized TMB to show an increasing blue color. Dichlorvos, as the samples, with the limit of 0.024 μg/L. Overall, we believe that the colorimetric probe can be used for the rapid, low-cost, and large-scale field detection of OPs in food samples. [ABSTRACT FROM AUTHOR]

Four new cyclopropane-based bisoxazolines were synthesized and applied to cobalt-catalyzed cross-coupling reactions between racemic α-bromo esters and aryl Grignard reagents. The reaction afforded a series of chiral α-arylalkanoic esters with high yields and good enantioselectivities (up to 93% yield, 92:8 er). This research focuses on the cross-coupling between racemic α-bromopropanoate and p -isobutylphenyl Grignard reagent’s which provides ibuprofen ester efficiently. Furthermore, ibuprofen ester 7e was transformed into ( S )-ibuprofen (99:1 er) via hydrolysis and recrystallization. [ABSTRACT FROM AUTHOR]

Abstract: Six optically active α-hydroxyl-β,γ-unsaturated acid esters 1a to 1f were synthesised, and they are significant moieties of the cerebrosides. The chiral intermediate alkynol 4 prepared by catalytic asymmetric addition had 99% ee, and which was converted into the target compounds 1a to 1f with high enantiomeric purity. [Copyright &y& Elsevier]

Abstract: A series of cyclopropane-based bisoxazolines were synthesized from (R)- and (S)-amino alcohols, and applied to copper-catalyzed enantioselective nitroaldol reactions between nitromethane and various aldehydes. The reactions generated β-hydroxy nitroalkanes in high yields (97%) and with good enantioselectivities (up to 87% ee). The effects of the oxazoline stereocenters constructed in the Henry reactions were also studied. [Copyright &y& Elsevier]

Abstract: The thermal [3+2] cycloaddition reactions of two classes of azomethine imines with allenoates have been investigated. The reactions are operationally simple and proceed smoothly under mild reaction conditions to provide a variety of dinitrogen-fused heterocycles in moderate to excellent yields. [Copyright &y& Elsevier]

Abstract: The enantioselective Henry reaction between nitromethane and various aldehydes catalyzed by chiral amino alcohol–Zn complex was described. The resulting β-nitroalcohols were obtained in high yields and with moderate to good enantiomeric excesses. [Copyright &y& Elsevier]

Abstract: A new amino alcohol with a chiral cyclopropane backbone has been developed and used in the catalytic asymmetric diethylzinc addition to various types of α-ketoesters. This cyclopropane-based chiral amino alcohol shows moderate enantioselectivity in the addition of organozinc to α-ketoesters. For dimethylzinc addition to α-ketoesters, up to 81% ee are obtained, respectively. [Copyright &y& Elsevier]

Abstract: Sequential [3+2] cycloaddition/rearrangement reaction of imidazolone nitrones and allenoates is described. The reaction was carried out in refluxing toluene to provide the methylene imidazolidinone derivatives in high yield. It provides a simple and convenient strategy for the synthesis of functionalized imidazolidinones. [Copyright &y& Elsevier]