Search

The ruthenium complexes [Ru[([H.sub.3]CC([CH.sub.2][PPh.sub.2]).sub.3]-[K.sup.3]-P)[([NCCH.sub.3]).sub.3]][(OTf).sub.2] [(1, ([H.sub.3]CC([CH.sub.2][PPh.sub.2]).sub.3] = triphos) and [Ru[(N([CH.sub.2][PPh.sub.2]).sub.3]-[K.sup.3]-P)[([NCCH.sub.3]).sub.3]][(OTf).sub.2] [(2, N([CH.sub.2][PPh.sub.2]).sub.3] = N-triphos) have been evaluated as homogeneous ionic hydrogenation catalysts for the catalytic hydrodeoxygenation of furfuryl alcohol and furfuryl acetate to 1,4-pentanediol and cyclopentanol in aqueous media reaction mixtures. For furfuryl alcohol, only marginal yields of 1,4-pentanediol could be achieved with mass balance deficiencies due to humin formation ranging from 67% to 90%. Attempts to improve the catalytic activity of 2 by enhancing its water solubility by nitrogen protonation and (or) methylation failed. Employing the less self-reactive furfuryl acetate as the substrate substantially diminishes humin formation, yielding up to 43% of 1,4-pentanediol and 19% of cyclopentanol (via Piancatelli rearrangement) with 1 and up to 33% of 1,4-pentanediol and 5% of cyclopentanol with 2. A design of experiments study was used to determine and compare the yield responses of the multiple parallel reaction channels with 1,4-pentanediol, cyclopentanol, and humins as a function of reaction temperature, time, catalyst load, and substrate concentration. This explores the correlations between these parameters and their impact on the reaction outcome and suggests an extremely complex overall reaction cascade of interdependent pathways of both acidand metal-catalyzed steps with some significant differences emerging between the two catalysts. Key words: hydrodeoxygenation, hydrogenation, homogeneous catalysis, sugar derivatives, biomass conversion, diols, design of experiments. Nous avons evalue les complexes de ruthenium [Ru[([H.sub.3]CC([CH.sub.2][PPh.sub.2]).sub.3]-[K.sup.3]-P)[([NCCH.sub.3]).sub.3]][(OTf).sub.2] [(1, ([H.sub.3]CC([CH.sub.2][PPh.sub.2]).sub.3] = triphos) et [Ru[(N([CH.sub.2][PPh.sub.2]).sub.3]-[K.sup.3]-P)[([NCCH.sub.3]).sub.3]][(OTf).sub.2] [(2, N([CH.sub.2][PPh.sub.2]).sub.3] = N-triphos) comme catalyseurs homogenes d'hydrogenation ionique pour effectuer l'hydrodesoxygenation catalytique de l'alcool furfurylique et de l'acetate de furfuryle en 1,4-pentanediol et en cyclopentanol dans des melanges reactionnels en milieu aqueux. Dans le cas de l'alcool furfurylique, le 1,4-pentanediol n'a ete obtenu qu'en faibles rendements et avec un bilan massique deficitaire en raison de la formation d'humines dans des proportions variant de 67 a 90 %. Nous avons tente, sans succes, d'ameliorer l'activite catalytique du complexe 2 en augmentant sa solubilite aqueuse par protonation ou par methylation des atomes d'azote, ou une combinaison de ces deux methodes. En employant l'acetate de furfuryle, qui est moins autoreactif, nous sommes parvenus a diminuer de maniere substantielle la formation d'humines et a produire jusqu'a 43 % de 1,4-pentanediol et 19 % de cyclopentanol (par rearrangement de Piancatelli) avec le catalyseur 1, et jusqu'a 33 % de 1,4-pentanediol et 5 % de cyclopentanol avec le catalyseur 2. Nous avons utilise une approche de type <> pour determiner et comparer les rendements resultant des differentes voies reactionnelles paralleles menant au 1,4-pentanediol, au cyclopentanol et aux humines en fonction de la temperature, du temps de reaction, de la charge catalytique et de la concentration du substrat. Cette approche permet d'explorer les correlations entre ces parametres et les effets de ces derniers sur les produits de la reaction. Le processus global est vraisemblablement le resultat d'une cascade extremement complexe de reactions interdependantes catalysees tant par l'acide que par le metal dont certaines etapes revelent des differences significatives entre les deux catalyseurs. [Traduit par la Redaction] Mots-cles : hydrodesoxygenation, hydrogenation, catalyse homogene, derives de sucres, transformation de la biomasse, diols, plan d'experiences., Introduction Because of their direct applicability in polyester and polyurethane formulations, [alpha],[omega]- and [beta],[gamma]-type diols are some of the most valuable chemicals that can potentially be derived from carbohydrate biomass. [...]

A kinetic study is reported on nucleophilic substitution reactions of p-nitrophenyl acetate (1a) with three [alpha]-effect nucleophiles, benzohydroxamate ([BHA.sup.-]), p-methylbenzohydroxamate ([MBHA.sup.-]), and p-methyl-N-methylbenzohydroxamate ([M.sub.2][BHA.sup.-]), and a reference nucleophile, m-chlorophenoxide (m-[ClPhO.sup-]), in DMSO-[H.sub.2]O mixtures of varying compositions at 25.0 [+ or -] 0.1 [degrees]C. Second-order rate constants for the reactions with [BHA.sup.-] and [MBHA.sup.-] decrease upon addition of DMSO to the reaction medium up to 60 mol % DMSO and then increase thereafter only a little. In contrast, [M.sub.2][BHA.sup.-] and m-[ClPhO.sup.-] become much more reactive as the DMSO content in the medium increases. Such contrasting medium effects on reactivity are consistent with the report that hydroxamic acids behave as OH acids in [H.sub.2]O but as NH acids in dipolar aprotic solvents (e.g., DMSO and MeCN). It has been concluded that [BHA.sup-] and [MBHA.sup-] form an equilibrium of a reactive form I with less reactive species II in DMSO-[H.sub.2]O mixtures and the position of the equilibrium is dependent on solvent compositions. BHA' and MBHA' exhibit the [alpha]-effect in [H.sub.2]O but not in in 90 mol % DMSO. In contrast, the [alpha]-effect yielded by [M.sub.2][BHA.sup-] increases steeply up to 70 mol % DMSO and then levels off thereafter. Key words: [alpha]-effect, medium effect, hydroxamates, transition state, ground state. Nous avons réalisé une étude cinétique sur les réactions de substitution nucléophile de l'acétate de p-nitrophényl (1a) avec trois nucléophiles à effet [alpha], soit le benzhydroxamate ([BHA.sup-]), p-méthylbenzhydroxamate ([MBHA.sup-]) et le p-méthyl-N-méthylbenzhydroxamate ([M.sub.2][BHA.sup-]), ainsi qu'avec un nucléophile de référence, le m-chlorophénoxyde (m-[ClPhO.sup-]), à 25,0 [+ or -] 0, 1 [degrees]C dans des mélanges contenant différentes proportions de DMSO-[H.sub.2]O. À mesure que nous ajoutions du DMSO dans le milieu réactionnel, nous avons observé que les constantes de vitesse de second ordre des réactions avec le [BHA.sup-] et le [MBHA.sup-] diminuaient jusqu'à 60 % mol de DMSO, puis n'augmentaient que légèrement au-delà de cette concentration. Par contre, le [M.sub.2][BHA.sup-] et le m-[ClPhO.sup.-] devenaient beaucoup plus réactifs à mesure que la concentration de DMSO dans le milieu augmentait. Des effets du milieu sur la réactivité si opposés sont en accord avec le fait rapporté que les acides hydroxamiques se comportent comme des acides à OH dans l'eau, mais comme des acides à NH dans les solvants dipolaires aprotiques (notamment le DMSO et le MeCN). Nous avons conclu que, dans le cas du [BHA.sup.-] et du [MBHA.sup.-], un équilibre s'établit entre une forme réactive I et des espèces moins réactives II dans les mélanges de DMSO-[H.sub.2]O et que la position de l'équilibre dépend de la composition du solvant. Le [BHA.sup.-] et le [MBHA.sup.-] présentent l'effet a dans le [H.sub.2]O, mais non dans le DMSO à 90 % mol. À l'inverse, l'effet a produit par le [M.sub.2][BHA.sup.-] augmente drastiquement jusqu'à une concentration de DMSO de 70 % mol, puis se stabilise au-delà de cette concentration. [Traduit par la Rédaction] Mots-clés : effet a, effet du milieu, hydroxamates, état de transition, état fondamental., Introduction Nucleophiles possessing lone-pair electrons at the atom [alpha] to the nucleophilic site have been reported to exhibit higher nucleophilic reactivity than similarly basic normal nucleophiles. (1-18) Thus, the enhanced [...]

We report here a selective, efficient and very simple receptor which can easily detect [F.sup.-] in the presence of a wide range of other anions [[Cl.sup.-], [Br.sup.-], [I.sup.-], [HSO.sup.-] [NO.sup.-], Acetate ([AcO.sup.-]) and Benzoate ([BzO.sup.-])] by use of colorimetric or fluorometric detection. 4-Chloro-2,6-fc(hydroxymethyl) phenol (CBHMP) is a simple and available phenolic receptor having no special chromophoric function. In this colorimetric method, naked-eye detection of [F.sup.-] with CBHMP is described. Interestingly, fluorometric detection of [F.sup.-] is also possible by highly selective fluorescent quenching response CBHMP in dimethyl sulfoxide (DMSO) media. Keywords: 4-chloro-2,6-bis(hydroxyrnethyl) phenol, colorimetry, fluorometry, fluoride, chromophore DOI: 10.1134/S1061934814020130, It is well known that anions play an important role in a wide range of chemical and biological processes; therefore the search for chemosensors for recognizing and sensing anions has [...]

Isotope labeled tracers are commonly used to quantify the turnover rates of various metabolic intermediates and yield information regarding physiological regulation. Studies often only consider either one nutritional state (fasted or fed) and/or one question (e.g., measure of lipid or protein turnover). In this article, we consider a novel application combining the global approach of metabonomics with widespread stable isotope labeling as a way of being able to map metabolism in open mammalian systems, an approach we call 'isotopomics'. A total of 45 15-week-old male Zucker rats were administrated different amounts (from 0.5 to 8 mmol/kg) of sodium [1,2-[sup.13][C.sub.2]] acetate. Plasma samples taken at 1, 4, and 24 h were analyzed with [sup.13]C nuclear magnetic resonance (NMR) and gas chromatography/mass spectrometry (GC/MS) to measure [sup.13]C isotopic enrichment of 39 plasma metubolites across a wide range of compound classes (amino acids, short-chain fatty acids, lactate, glucose, and free fatty acids). Isotopic enrichment from 0.1-7.1 mole percent excess (MPE) for the highest dose could be reliably measured in 16 metabolites, and the kinetics of their [sup.13]C isotopic enrichment are reported. Clustering metabolites based on [sup.13]C kinetic curves enabled highlighting of time dependent patterns of 13C distribution through the key metabolic pathways. These kinetic and quantitative data were reported into a biochemical map. This type of isotopomic approach for mapping dynamic metabolism in an open system has great potential for advancing our mechanistic knowledge of how different interventions and diseases can impact the metabolic response of animals and humans. 10.1021/ac902086g

The highly enantioselective synthesis of 2-oxo and 3-oxo pyrrolidines was carried out by using diastereoselective addition of the lithium enolate of [alpha]-diazoacetoacetate to chiral N-sulfinyl. The transformation approach provides a new route to 5-substituted 2-oxo and 3-oxo pyrrolidines with high enantiomeric purity.

Picosecond pump-probe spectroscopy is used for studying the conversion of benzhydryl acetate geminate radical pairs to contact ion pairs following photoinduced homolysis in solution. The mechanism for the decay of the geminate radical pair onto the ground state surface is ascribed to a nonadiabatic electron-transfer process and the kinetics for the process has occurred within the inverted regime for electron transfer.

The direct analysis of tissue from both the central and peripheral nervous systems of control rats and those administered the potential neurotoxin dichloroacetate (DCA) was investigated using an intermediate-pressure matrix-assisted laser desorption/ionization (IP-MALDI) source coupled to a linear ion trap (LIT) mass spectrometer. The matrix, 2,5-dihydroxybenzoic acid, was applied to the tissue using a novel automated inkjet printer system. The [MS.sup.n] capabilities of the LIT allowed identification of lipids desorbed directly from tissue. A marked decrease is observed in the intensity of lipid ions in spinal cord and sciatic nerve tissues from rats exposed to DCA. The results also demonstrate the rapid, sensitive, and semiquantitative capabilities of this method.

Fluorescence imaging and microbial analysis were used to assess biodegradation processes in a laboratory scale groundwater contaminant plume. The results showed that plume behavior can be best described by growth and decay of active biomass as a single functional group of organisms represented by active cell counts.

The cascade synthesis of polyoxygenated tetracyclic 6H, 11H-[2]benzopyrano-[4,3-c][1]benzopyran-11-ones 1, by the combination of polymethoxy-containing coumarin and 1H-2-benzopyran structural subunits is studied. It is found that the compounds undergo a sequence of reactions namely deprotection, halogenation and annulation to give a good yield of polyoxygenated tetracyclic 6H, 11H-[2]benzopyrano-[4,3-c][1]benzopyran-11-ones and that some of them show a moderate cytotoxicity against human epithelial mammary HBL100 cells.

The structural and spectroscopic characterization of a series of trinuclear and tetranuclear vanadium(III)/carboxylate complexes of acetate and related derivatives are described. The results have shown that these complexes are not purely solid-state phenomena but are also present in solution.

Symmetric hierarchical hollow PbS structures consisting of nanowalls are successfully fabricated by a facile solvothermal process in ethylenediamine, employing lead acetate trihydrate and dithizone as precursors. The results have shown that the temperatures, solvent and sulfur sources play vital role on the morphologies and sizes of the symmetric hierarchical hollow PbS microcrystals.

The preparation of the Beta-fluorinated derivative of the 1,3-dipyrrolyl-1,3-propanedione B[F.sub.2] complex from 3,4-difluoropyrrole and malonyl chloride, followed by treatment with B[F.sub.3].O[Et.sub.2] is presented. Results show that, despite the simple, acyclic, and neutral structure, the Beta-fluorinated derivative exhibits efficient 1:1 binding for anions in C[H.sub.2][Cl.sub.2] using the bridging CH and pyrrole NH as interaction sites.

The consumption of acetate in soils taken from a nutrient gradient in the northern Florida Everglades was studied by stable istope probing. It indicated that a significant amount of acetate was consumed by syntrophic acetate oxidation in nutrient-enriched soil.

The results obtained in the laboratory by studying the butylaminolysis of 4-nitrophenyl acetate (NPA) in chlorobenzene in the presence of glyms or crown ethers are reported. Glymes were chosen on the basis of Hogan and Gandour's studies, which conclude that a glyme with four oxygen atoms in a -[[C[H.sub.2]OC[H.sub.2]].sub.4]- type subunit provides optimal catalysis for this kind of processes.

A general and high-yielding methodology is developed for the Suzuki reaction in aqueous phase in a short reaction time under mild conditions. This method is useful and attractive for the synthesis of biaryls due to its high efficiency and use of only cosolvent without other additives and ligands.

A short and high-yielding synthesis is devised to prepare C-linked 2-deoxy-2-acetamido-alpha-D-galactopyranose derivative (3). One of the main advantages of this approach is that it employs commercially available and inexpensive D-glucosamine as the starting material.

The mechanism of the stereospecific gold(I)-catalyzed Rautenstrauch rearrangement of (E)-1-ethynyl-2-methyl-but-2-en-yl acetate to 2,4-dimethyl-cyclopent-2-enone is computationally addressed using density functional theory (DFT). Results indicate that the fidelity of the center-to-helix-to-center chirality transfer requires that the rates of helix interconversion and pivaloyl rotation are slower than the cyclization, as predicted by calculations.

The solvent effect study on the alpha-effect, second-order rate constants are determined spectrophotometrically for reactions of a series of substituted phenyl acetates with butan-2,3-dione monoximate and p-chlorophenoxide, in dimethyl sulfoxide-H2O mixtures of varying compositions. Through application of calorimetric measurements of ground-state solvation combined with the diagnostic beta(sub nuc) values, it is shown that the transition-state effect is more dominant than the ground-state effect.

The applicability of transition-metal (TM)-monosubstituted Keggin polyoxometalates (POMs) and TM-carboxylate cationic complexes for the synthesis of new magically attractive hybrid compounds are explored. Electron paramagnetic resonance studies indicate that both the supported [Cu(sub 2)(ac)(sub 2)(phen)(sub 2)(H(sub 2)O)](super 2+) complexes and the copper(II)-monosubstituted Psos are magnetically isolated.

C-H functionalization of benzyl silyl ethers by means of rhodium-catalyzed insertions of aryldiazoacetates can be achieved in a highly diastereoselective and enantioselective manner by judicious choice of chiral catalyst or auxiliary. The use of (S)-lactate as a chiral auxiliary resulted in C-H functionalization with moderately high diastereoselectivity (79-88% de) and enantioselectivity (68-85% ee).

The ultrasonic velocities, densities, viscosities, and electrical conductivities of aqueous solutions of magnesium nitrate and magnesium acetate is measured from dilute to saturation concentrations. The experimental results are supported by molecular dynamics simulations, which reveal the much stronger tendency of OAc(super -) compared to NO(sub 3)(super -) to associate with Mg(super 2+) in aqueous solutions.

A new approach is presented for the preparation of metal-organic lanthanide sol-gel precursor and its application for the production of coated conductors. It is found that there are two separate structures for hydrated yttrium acetates, which is an intermediate in the building of ceramic oxide layers for coated conductors.

Several computational methods are presented to calculate the pKa values of acetate and bicarbonate anions in the aqueous solution. The results showed that QM/MM-Ewald simulations give an accurate and consistent evaluation of the pKa values of acetate and bicarbonate based on both the relative and absolute pKa formulas, while other methods could yield satisfactory results only for certain calculations.

A cross-coupling reaction between acetates of Baylis-Hillman adducts and organosilanes is described. A nonconventional solvent poly(ethylene glycol) (PEG) is used as the reaction medium.

The activation parameters for bond formation are examined within the context of the Hynes theory for solvent dynamical effects on the passage through the transition state. Factors that control nucleophilicity are discussed and the validity of applying the Marcus equation to the SN1 reaction mechanism is addressed.

The glycosylation with trichloroacetimides derived from different glycopyranoses bearing a nonparticipating group at C-2 was explored in different ionic liquids as solvents. The stereoselectivity was significantly affected by the reaction media and by the anomeric configuration.

A detailed reaction coordinate analysis for the Acinetobacter johnsonii (Dke1)-catalyzed conversion of 2,4-pentanedione (PD) into the C-3 peroxidate intermediate, which decomposes into the products, is reported. An oxidative carbon-carbon bond cleavage by Dke1 is triggered from a C-3 peroxidate intermediate that performs an intramolecular nucleophilic attack on the adjacent carbonyl group.

Allylic acetate esters containing a variety of N-arylsulfonyl sulfoximines on the acetyl residue were prepared in a study and submitted to the decarboxylative Claisen rearrangement reaction. Rearranged products were isolated in generally good yields, and diastereoselectivities up to 82:18 were obtained.

There are notable differences in reactivity between arylpalladium(II) intermediates generated by carboxylative palladation and those produced in conventional Heck reactions. The more electron-rich alkenes react preferentially with an arylpalladium(II) trifluoroacetate intermediate formed by decarboxylative palladation whereas an opposite trend is found in conventional Heck reactions.

Four new stilbene-type monomers with an acetal masked aldehyde group connected to a dipropyl- or dipropoxy-substituted benzene ring, and a phosphonate ester group connected to either benzene, thiophene, or a benzothiadiazole ring are prepared. A terpyridine end-functionalized trimer and a heterotrimer with a mixed composition of monomers are also prepared.

A simple, efficient, and highly practical method is developed to promote the Knoevenagel aldol reaction where mucohalic acids are used as starting material, giving gamma-functionalized gamma-butenolides in good to excellent yield. Indium acetate turned out to be a novel, green Lewis acid to promote this reaction for addition of diverse types of active methylene compounds such as dialkyl malonate, alkyl cyanoacetate, ethyl malonate monoamide, and ethyl nitracetate to mucochloric acid.

The catalytic enantioselective addition of an acetate enolate equivalent to ketones is described. The results show that methyl trichlorosilyl ketene acetal reacts with a wide range of ketones in the presence of pyridine N-oxide to afford the aldol addition products in excellent yields.

The monooxo Re(V) core is conveniently stabilized by tripodal scorpionate ligands comprising carboxylate or sulfonate tails, giving a series of intermediate complexes of the type Re(O)(NNO)Cl(X) (X=Cl), whose structure depends on the type of NNO ligand and solvent utilized. The presence of 3,5-substituted pz in the NNO framework is crucial for further replacement of monodentate groups giving stable '3+2' mixed ligand groups.

The structural and conformational properties of two sulfenyl derivatives, trifluoromethanesulfenyl acetate, CF(sub 3)S-OC(O)CH(sub 3), and trifluoromethanesulfenyl trifluoroacetate, CF(sub 3)S-OC(O)CF(sup 3) are determined. The predominant conformer possesses a gauche structure with the C=O bonds of both CF3C(O) groups synperiplanar to the S-O bond and a trans structure around the S-O bond corresponds to a transition state.

A study of published crystal structures suggests that the exocyclic C-O bond in acetate esters of cyclic alcohols intrinsically prefers a staggered conformation, although the eclipsed conformation is only slightly less stable. MM3 molecular mechanics calculations of some simple model acetates as well as measurements of NMR coupling constants of these acetates are reported.

The synthesis of new 18-membered hexaazamacrocycles containing a functionalized 2,2':6'2'-terpyridine moiety as a part of the cyclic backbone and three acetate pendant arms is described. The photophysical properties of the Eu(III) complexes derived from these ligands were examined in aqueous solutions.

Carbon monoxide, formate, and acetate interact with horseradish peroxidase (HRP) by binding to subsites within the active site. A description of high-resolution crystal structures for HRP in its complexes with carbon monoxide and with formate is given.

The reactivities of zinc(II) with three tetraiminodiphenol macrocycles [H(sub 4)L(super 1-3)](ClO4)(sub 2) with varying [CH(sub 2)](sub n) lateral chains are studied spectrophotometrically and spectrofluorimetrically. The photoluminescence behavior of a series of para-substituted benzenecarboxylate-bridged complexes [Zn(sub 2)L(super 2)(mu-O(sub 2)CR)](super +) shows that the intensity of luminescence increases with the electron-releasing substitutes.

The well-known Vogel-Fulcher-Tammann-Hesse equation is extensively used in the description of cooperative molecular motion in glass-forming liquids. The analysis of this experimental data concluded that correlation exists mainly between the B and T(sub 0) parameters.

The pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectrum of OCS in a cold supersonic expansion was measured. The analysis led to the characterization of the Renner-Teller effect, of the spin-orbit interaction, and Fermi interactions between CS-stretching and bending levels of the A(super +) (super 2)Pi state of OCS(super +).

Investigating the part of the ongoing research commercial Lewis acid, Bronsted acid and substitutent effects studies are utilized in the determination of what effects and control the formation of 3-hydroxyacrylates are described. The results of these studies indicate that both HBF4-OET2 and 1 are efficient catalysts for the formation of 3-hydroxyacrylates from aromatic aldehydes and EDA.

The effect of the leaving group on the reaction rate and branching ration is investigated using a methodology developed for studying the product distributions of gas-phase SN2 and E2 reactions. The previous condensed phase data indicate a reactivity order of iodide > bromide > trifluoroacetate for substitution reactions, however the basicities of bromide and trifluoroacetate are reversed in the condensed phase so the reactivity pattern does not reflect the relative re action exothermicities.

A strategy that enables resin-bound bismuth to be utilized as a multidirectional linker in SPOS is presented. For solid-phase organic synthesis and as a resin-bound arylation reagent resin-bound bismuth has been used as part of a multidirectional linker system for the fist time.

An investigation on the adsorption of formate and acetate on the Ni(110) surface is presented with STM, LEED, TPRS, and XPS. The study concluded that the added Ni in the formate structure facilities the decomposition of formate into CO2, H2, and scattered Ni(sub x) nuclei, which act as sites for further formate decomposition.

The interaction between dioctadecyldimethylammonium bromide (DODAB), chloride (DODAC), or acetate (DODAAc) cationic bilayer fragments (BF) and polystyrene sulfate (PSS) particles is examined, by means of zeta-potential, and particle diameter analysis, at and above equivalence of total surface areas for bilayers and particles (A(sub b)/A(sub p)) over a range of low NaCl and lipid concentrations.

Investigation of biosynthesis of lambertellols A and B as well as lambertellin was done by isotope labeling experiments. Nearly 40 percent of specific incorporation of [1,2-(super 13)C(sub 2)] acetate was achieved, and all carbons in lambertellols A and lambertellols B were labeled.

The active enantiomers of the pheromones of pine sawflies were obtained by an efficient total synthesis of (2S,3S,7S)-3,7-dimethylpentadecan-2-yl acetate and propionate. The synthesis was not only efficient but also allowed the establishment of all the three chiral centers of (2S,3S,7S)-1 from L-malic acid.