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The treatment of readily available N-alkynyl-5-iodo-6-sulfamido-pyrimidines with iPrMgCl⋅LiCl followed by a transmetalation with CuCN⋅2 LiCl produces, after intramolecular carbocupration, metalated py rrolo[2,3- d]pyrimidines. Quenching of these pyrimidines with allylic halides or acid chlorides results in polyfunctional pyrrolo[2,3- d]pyrimidines. Further reaction with ICl and a Negishi cross-coupling, using PEPPSI- iPr as the catalyst, furnishes fully substituted N-heterocycles. A formal synthesis of the marine alkaloid rigidin A has been achieved as well as the preparation of a derivative of 7-azaserotonine, related to the natural hormone serotonin. [ABSTRACT FROM AUTHOR]

Heavier group 14 multiple bonds have intrigued chemists since more than a century. The synthesis of stable compounds with double and triple bonds with silicon, germanium, tin and lead had considerable impact on modern ideas of chemical bonding. These developments were made possible by the use of bulky substituents that provide kinetic and thermodynamic protection. Since about a decade the compatibility of heavier multiple bonds with various functional groups has moved into focus. This review covers multiply bonded group 14 species with at least one additional reactive site. The vinylic functionalities of groups 1 and 17, resulting in nucleophilic and electrophilic disila vinyl groups, respectively, are the most prevalent and well-studied. They have been employed repeatedly for the transfer of heavier multiple bonds to yield low-valent group 14 compounds with novel structural motifs. Vinylic functionalities of groups 2 to 16 and a few σ-bonded transition metal complexes are experimentally known, but their reactivity has been studied to a lesser extent. Donor-coordinated multiple bonds are a relatively new field of research, but the large degree of unsaturation as isomers of alkynes (as well as residual functionality in some cases) offers considerable possibility for further manipulation, e.g. for the incorporation into more extended systems. Heavier allyl halides constitute the major part of heavier multiple bonds with a functional group in allylic position and some examples of successful transformations are given. At present, remote functionalities are basically limited to para-phenylene functionalised disilenes. The reported use of the latter for further derivatisation might encourage investigations in this direction. In summary, the study of peripherally functionalised multiple bonds with heavier group 14 elements is already well beyond its infancy and may be an instrumental factor in awakening the potential of group 14 chemistry for applications in polymers and other materials. [ABSTRACT FROM AUTHOR]

The reaction of tin(II) and tin(IV) mono- o -amidophenolate complexes based on redox-active 4,6-di- tert -butyl-N-(2,6-di- iso -propylphenyl)-o-aminophenol ( dipp APH 2 ) with allylhalides is reported. This process includes oxidative addition of all-Hal (where all = allyl, Hal = Cl, Br, I) molecule to the non-transition metal complex and results in the alkyl transfer to carbon ring with the formation of new C C coupled product. The interaction proceeds at room temperature and gives new tin(IV) derivatives containing iminocyclohexa-1,4-dienolate ligand. The “oxidative addition” type products have been characterized by X-ray crystallography. [ABSTRACT FROM AUTHOR]

New reactivity of a [Cu(NHC)] (NHC=N-heterocyclic carbene) catalyst is disclosed for the efficient C−H allylation of polyfluoroarenes using allyl halides in benzene at room temperature. The same catalyst system also promotes an isomerization-induced alkenylation of initially the generated allyl arenes when the reaction is run in tetrahydrofuran. Significantly, not only electron-deficient but also electron-rich (hetero)arenes undergo this double-bond migration process, thus leading to alkenylated products. The present system features mild reaction conditions, broad scope with respect to the arene substrates and allyl halide reactants, good functional-group tolerance, and high stereoselectivity. [ABSTRACT FROM AUTHOR]

In honor of the 97th birthday of Professor John D. Roberts, the author has assembled a collection of poignant quotes and anecdotes, mostly written by Roberts himself, which embody his philosophies of life and his wide-ranging experiences and interests. A brief summary of Roberts's major scientific accomplishments is also presented. [ABSTRACT FROM AUTHOR]

Inrecent years, methylammonium lead halide (MAPbX3, whereX = Cl, Br, and I) perovskites have attracted tremendous interestcaused by their outstanding photovoltaic performance. Mixed halideshave been frequently used as the active layer of solar cells, as aresult of their superior physical properties as compared to thoseof traditionally used pure iodide. Herein, we report a remarkablefinding of reversible halide-exchange reactions of MAPbX3, which facilitates the synthesis of a series of mixed halide perovskites.We synthesized MAPbBr3plate-type nanocrystals (NCs) asa starting material by a novel solution reaction using octylamineas the capping ligand. The synthesis of MAPbBr3–xClxand MAPbBr3–xIxNCs was achieved bythe halide exchange reaction of MAPbBr3with MACl and MAI,respectively, in an isopropyl alcohol solution, demonstrating full-range band gaptuning over a wide range (1.6–3 eV). Moreover, photodetectorswere fabricated using these composition-tuned NCs; a strong correlationwas observed between the photocurrent and photoluminescence decaytime. Among the two mixed halide perovskite series, those with I-richcomposition (x= 2), where a sole tetragonal phaseexists without the incorporation of a cubic phase, exhibited the highestphotoconversion efficiency. To understand the composition-dependentphotoconversion efficiency, first-principles density-functional theorycalculations were carried out, which predicted many plausible configurationsfor cubic and tetragonal phase mixed halides. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of organophosphonates through palladium-catalyzed coupling of α-diazo phosphonates with benzyl or allyl halides has been developed. Trisubstituted alkenylphosphonates bearing versatile functional groups can be easily accessed in good yields and with excellent stereoselectivity through this method. Moreover, with similar strategy a-substituted vinylphosphonates can also be attained by the palladium-catalyzed coupling reaction of N-tosylhydrazones and aryl bromides. Migratory insertion of palladium carbene is proposed as the key step in this reaction. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed three-component cascade reaction of 2-(2-enynyl)pyridines with nucleophiles and allyl halides has been developed, enabling the synthesis of densely functionalized indolizines in moderate to good yields. The newly developed methodology offers several practical advantages, including operational simplicity, ready availability of starting materials, and mild reaction conditions. [ABSTRACT FROM AUTHOR]

Fluorinated 2-(p-tolylsulfinyl)benzyl carbanions react with allyl and propargyl halides in a highly stereoselective way, providing homoallylic and homopropargylic fluorides, respectively, with high optical purity. Theoretical calculations found transition states for these transformations whose relative stabilities are consistent with the experimentally observed stereoselectivity. [ABSTRACT FROM AUTHOR]

Heating a mixture of (2 R*,3 R*)- and (2 R*,3 S*)-2-[(1 S*)-1-iodoethyl]-3,5-dimethyl-1-[(2-nitrophenyl) sulfonyl]indolines with N-isopropylpiperidine in xylene resulted in (2 S*,3 R*)-3,5-dimethyl-1-[(2-nitrophenyl) sulfonyl]-2-vinylindoline. The latter reacted with thiophenol to afford (2 S*,3 R*)-3,5-dimethyl-2-vinylindoline, whose reaction with allyl halides or acetyl bromide gave rise to N-allyl-, N-propenyl-, or N-acetyl derivatives. Nitration of 1-acetyl-3,5-dimethyl-2-vinylindoline yielded ortho-nitro derivative. [ABSTRACT FROM AUTHOR]

A reaction of tin(IV) bis- o-amidophenolate complex based on redox-active 4,6-di- tert-butyl- N-(2,6-diisopropylphenyl)- o-aminophenol with various allyl halides was studied. This process includes the addition of 1 equiv. of allyl halide to the starting complex and is accompanied by the change in the redox state of one of the redox-active ligands. The reaction results in the formation of a new carbon-carbon bond between the allylic fragment and the carbon atom at position 5 of the ligand o-iminoquinone ring, as well as a tin-halogen bond. The structure and composition of compounds synthesized were confirmed by ESR, NMR, and IR spectroscopy and elemental analysis. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and characterization of the new bis-o-amidophenolate gallium(III) complex are reported. This compound was found to be reactive towards allyl halides at room temperature. The addition of two allyl halide molecules to the original complex accompanied with two new C–C bonds formation has been observed. The structures of the products obtained were confirmed by 1H NMR and X-ray diffraction analysis. [Copyright &y& Elsevier]

The scope of palladium-catalyzed, auxiliary-assisted direct arylation and alkylation of sp² and sp³ C-H bonds of amine and carboxylic acid derivatives has been investigated. The method employs a palladium acetate catalyst, substrate, aryl, alkyl, benzyl, or allyl halide, and inorganic base in tert-amyl alcohol or water solvent at 100-140 °C. Aryl and alkyl iodides as well as benzyl and allyl bromides are competent reagents in this transformation. The picolinic acid auxiliary is used for amine γ-functionalization, and the 8-aminoquinoline auxiliary is used for carboxylic acid β-functionalization. Some optimization of base, additives, and solvent is required for achieving best results. [ABSTRACT FROM AUTHOR]

We examined the tandem alkylation/[2+4] cycloaddition of 1-(2-furyl)-3,4-dihydroisoquinolines by various allyl halides. It was found that the process occurred through the intermediate formation of 2-allyl-1-furyl-3,4-dihydroisoquinolinium salts with a subsequent intramolecular exo addition of the allyl fragment to the furan ring. The adducts obtained were structural analogs of the isoindolo-[1,2- a]isoquinoline alkaloids jamtine and hirsutine. [ABSTRACT FROM AUTHOR]

The cobalt-catalyzed cross-coupling of alkyl (pseudo)halides with alkyl Grignard reagents in the presence of 1,3-butadiene as a ligand precursor and LiI is described. Sterically congested quaternary carbon centers could be constructed by using tertiary alkyl Grignard reagents. This reaction proceeds via an ionic mechanism with inversion of stereochemistry at the reacting site of the alkyl halide and is compatible with various functional groups. The use of both 1,3-butadiene and LiI was essential for achieving high yields and high selectivities. [ABSTRACT FROM AUTHOR]

Three's a crowd: Tri ‐ and tetrasubstituted allyl allenes can be easily accessed by this CuI ‐ catalyzed three ‐ component coupling reaction of N ‐ tosylhydrazones, terminal alkynes, and allyl halides. The reaction proceeds through a mechanism involving copper carbene migratory insertion. [ABSTRACT FROM AUTHOR]

Abstract: A mild and operationally simple approach to highly functionalized oxazolones has been developed, which involves an intramolecular oxypalladation of N-alkynyl tert-butyloxycarbamates, followed by either protonolysis of the alkenyl C–Pd bond to afford 3,5-disubstituted oxazolones or allylation with allyl halides in the presence of Ag2CO3 to generate 3,4,5-trisubstituted oxazolones, respectively. [Copyright &y& Elsevier]

Highly efficient palladium-catalyzed carbonylation of aryl, alkenyl, and allyl halides with phenyl formate is reported. This procedure does not use carbon monoxide and affords one-carbon-elongated carboxylic acid phenyl esters in excellent yields. The reaction proceeds smoothly under mild conditions and tolerates a wide range of functional groups including aldehyde, ether, ketone, ester, and cyano groups. Furthermore, a variety of heteroaromatic bromides can be converted to the corresponding phenyl esters in high yields. [ABSTRACT FROM AUTHOR]

A novel example of the Suzuki--Miyaura cross-coupling reaction between sp³-carbon and sp³-carbon is described. The reaction of a diborylmethane derivative with allyl halides or benzyl halides proceeded efficiently in the presence of appropriate Pd-catalysts at room temperature. The present approaches provide functionalized homoallylboronates and alkylboronates with excellent regio- and chemoselectivities. [ABSTRACT FROM AUTHOR]

The complex [PtMe2(2,2′-bipyridine)], 1, reacts with allyl chloride and allyl bromide, to give [PtXMe2(CH2CHCH2)(2,2′-bipyridine)], 2, X = Cl; 3, X = Br, with 2-methylallyl chlorideto give [PtClMe2(CH2CMeCH2)(2,2′-bipyridine)], 4, and with crotyl chloride(a mixture of trans- and cis-MeCHCHCH2Cl), to give a mixture of [PtClMe2(trans-CH2CHCHMe)(2,2′-bipyridine)], 5, and [PtClMe2(cis-CH2CHCHMe)(2,2′-bipyridine)], 6. The complexes are formed mostly by transoxidative addition and, for the crotyl complexes, without allylicrearrangement. Complex 1reacts with CH2CHCHMeCl,mostly with allylic rearrangement, to give complex 5,with complexes 6and [PtClMe2(CHMeCHCH2)(2,2′-bipyridine)], 7, as minor products.The reactions of 1with CH2CHCH2X (X = Cl or Br) and MeCHCHCH2Cl followsecond-order kinetics (first-order in both reagents), but 1reacts with CH2CHCHMeCl by third-order kinetics(first-order in 1, second-order in CH2CHCHMeCl)and with CH2CMeCH2Cl by a mixture ofsecond- and third-order kinetics. The second-order reactions are proposedto occur by the SN2 mechanism, and potential mechanismsof the third-order reactions are discussed. [ABSTRACT FROM AUTHOR]

A mild and efficient one-pot synthesis of esters based on the Pd-catalyzed alkoxy- and aryloxycarbonylation of allylic and benzylic halides is described. The methodology has been applied to primary, secondary, and tertiary alcohols as well as to phenol derivatives. The O-protection of some biologically relevant molecules is also reported. [ABSTRACT FROM AUTHOR]

Abstract: An investigation was conducted to determine whether the cross-metathesis (CM) of allyl halides tolerates amide groups. The results show that the ruthenium-based complexes I–III serve as poor catalysts for the CM of allyl halides with olefins that contain an N,N-dimethylamide group. In contrast, the Grubbs–Hoveyda–Blechert second generation catalyst (III) efficiently promotes these processes with olefins bearing a Weinreb amide group. Lastly, a reinvestigation of the ester group tolerance of the allyl halide CM with unsaturated esters demonstrated that III serves as an efficient catalyst for these reactions. [Copyright &y& Elsevier]

This report describes the Pd(0)-catalyzed fluorination of linear allylic chlorides and bromides, yielding branched allylic fluorides in high selectivity. Many of the significant synthetic limitations previously associated with the preparation of these products are overcome by this catalytic method. We also demonstrate that a chiral bisphosphine-ligated palladium catalyst enables highly enantioselective access to a class of branched allylic fluorides that can be readily diversified to valuable fluorinated products. [ABSTRACT FROM AUTHOR]

The alkylation of 3-(2-hydroxyethyl)-1H,3H-quinazoline-2,4-dione and subsequent bromination of its 1-allyl derivative have been studied. The data obtained has been compared with the results of similar studies on a series of other, related compounds. A rule has been formulated which allows a prediction of 1-allyl-substituted 2-oxo azaheterocycles bromination route based upon the way in which their initial alkylation by allyl bromide in the system DMSO-KCO occurs. [ABSTRACT FROM AUTHOR]

The sequential use of Cu-catalyzed asymmetric allylic alkylation, olefin cross-metathesis, and Ir-catalyzed asymmetric allylic amination allows the concise, stereodivergent synthesis of complex chiral amines with complete regiocontrol and good diastereoselectivity, exemplified by the synthesis of a pair of diastereoisomeric unnatural branched amino acid derivatives. [ABSTRACT FROM AUTHOR]

By the B3P86/6-311G(3d,2p) method, remote substituent effects on trans-YCHCHCHF were investigated by examining their conformational stabilities, molecular geometries, and stereoelectronic interactions in this paper. The cis conformer is favored for YH, Cl, Me, Vinyl, CF, CN, CHO, and NO, whereas the gauche is favored for YOMe, OH. A correlation of Δ H with the substituent constants σ(Y) shows that the increasing electron-withdrawing ability of the substituent Y increases the relative stability of the cis conformer. It was found that the substituent effect on the molecule stabilization energies (relative to CHCHCHF) is more significant in the gauche conformers than in the cis conformers. In agreement, molecular structures of the gauche conformers were also observed to vary more significantly with the substitution than those of the cis conformers. By the second-order perturbation energy ( E(2)) in NBO analysis, it was found that the total C-C vicinal hyperconjugation is determinant in the enthalpy difference and consequently controls the conformational stability. Further analysis shows that the substituent effect on the C-C vicinal hyperconjugations is much higher in the gauche conformers than in the cis conformers. The highly sensitive π→σ* interaction to the substitution in the gauche conformers, is the leading factor in variation of molecular stability and geometry. Copyright © 2010 John Wiley & Sons, Ltd. In this paper, it was found that the conformational preference for the cis or gauche conformer in trans-YCH=CHCHF is highly related with the Y substitution. The substituent effect is transmitted through the double bond and influences the C−C vicinal hyperconjugations, which are the determinant factor for the conformational stability. [ABSTRACT FROM AUTHOR]

Thiol-containing peptides and cysteine have been successfully S-allylated with various allyl alcohols in aqueous medium containing a catalytic amount of [CpRu(η3-C3H5)(2-quinolinecarboxylato)]PF6. Quick and easy install of 2-propen-l-ol having a long-chain alkyl group at C(2) facilitates the synthesis of a new series of artificial lipopeptides, indicating a potential application to synthetic biology. [ABSTRACT FROM AUTHOR]

Abstract: New α-silylacetic acids have been prepared following a general and convenient procedure of a one-pot reaction between trimethylsilylacetate and different chlorosilanes. New derivatives of diphenyl(methyl)silylacetic acid were prepared by a direct alkylation of its dianion with benzyl-, allyl-, and alkyl halides and trimethylchlorogermane to afford new α-silylcarboxylic acids. [ABSTRACT FROM AUTHOR]

Abstract: The C-6 unit of methyl α-d-galactopyranoside was selectively modified by combining enzymatic oxidation with an indium-mediated allylation reaction. The Barbier–Grignard type reaction, where a carbonyl group reacts with an allyl halide, proceeds in aqueous solution, even with water as the only solvent; thus carbohydrates can be modified without the need for drying or protection–deprotection steps. The corresponding homoallyl alcohols are produced in high yields of >90% in the reactions with allyl bromide and cinnamyl chloride. The main products were isolated and characterized by GC–MS and NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Cationic, neutral, and anionic aluminum allyl compounds were synthesized,and their reactivity toward electrophiles was studied. The THF adductof the previously elusive tris(allyl)aluminum, [Al(η1-C3H5)3(THF)] (1),was isolated as an oil. Protonolysis of one allyl ligand in 1using [NEt3H][BPh4] gave the cationicbis(allyl)aluminum, a fragment of the crystalline [Al(η1-C3H5)2(THF)3−n][BPh4]−·(n)THF (n= 0, 1) (2). Single-crystal X-ray diffraction of [Al(η1-C3H5)2(THF)2][BPh4]−(2a) revealed atetrahedral aluminum center, while [Al(η1-C3H5)2(THF)3][BPh4]−(2b) contains a trigonal-bipyramidalaluminum center with both allyl ligands in the equatorial plane. Thetetrakis(allyl)aluminate K[Al(η1-C3H5)4]−(3) was also synthesized from the reaction of 1with K(C3H5). Reactions of the allyl compounds 1−3with (i) benzophenone, (ii) allyl halidesC3H5X (X = Cl, Br, I), and (iii) halogen X2(X = Br, I) showed considerable difference with respect tothe ionic charge of the aluminum allyl. [ABSTRACT FROM AUTHOR]

The unusual base-induced ring-enlargement of halomethylenecyclobutanes to 1-halocyclopentenes was examined with unsymmetrical and 13C-labeled substrates to study regio- and stereochemical characteristics. Migration of a ring carbon atom (single migration) or simultaneous migration of a ring carbon atom and the halide (double migration) gives the ring-enlarged products. 13C-labeling experiments established that both rearrangements occur with retention of configuration at the migrating center. These systems are suggested as models for the Fritsch-Buttenberg-Wiechell (FBW) rearrangement. [ABSTRACT FROM AUTHOR]

The intermediates and transition structures in the degenerate thermal rearrangements of bicyclo[4.4.0]deca-2,4,7,9-tetraene (1c), bicyclo[5.5.0]dodeca-2,4,8,10-tetraene (11b), and bicyclo[5.4.0]undeca- 2,4,8,10-tetraene (14) have been located by (U)B3LYP/6-31G(d) calculations. The singlet-triplet energy differences (ΔEST) in the diradical intermediates (tricyclo[4.4.0.02,7]deca-3,8-dien-5,10-diyl (2c), tricyclo[5.5.0.05,11]dodeca-2,8-dien-4,10-diyl (12b), and tricyclo[5.4.0.05,11]undeca-2,8-dien-4,10-diyl (15)) have been computed, using both UB3LYP and (6/6)CASPT2 calculations. ΔEST in 2c, in which a four-membered ring is anti-bridged by two allylic radicals, is computed to be larger by a factor of 5 than ΔEST in 15, in which the anti-bridged ring is five-membered, and by a factor of 10 than that in 12b, in which the anti-bridged ring is six-membered. The reasons for the much larger interaction between two allylic radicals through the bonds of the four-membered ring in 2c than through the bonds of the five-membered ring in 15 or the six-membered ring in 12b are discussed, and the consequences of the large, through-bond stabilization of the singlet state of 2c are described. [ABSTRACT FROM AUTHOR]

The [1.1.1]propellane radical cation 1·+, generated by radiolytic oxidation of the parent compound in argon and Freon matrices at low temperatures, undergoes a spontaneous rearrangement to form the distonic 1,1 -dimethyleneallene (or 2-vinylideneallyl) radical cation 3·+ consisting of an allyl radical substituted at the 2-position by a vinyl cation. In similar matrix studies, it is found that the isomeric dimethylenecyclo-propane radical cation 2·+ also rearranges to 3·+. The unusual molecular and electronic structure of 3~ has been established by the results of ESR, UV-vis, and IR spectroscopic measurements in conjunction with detailed theoretical calculations. Also of particular interest is an NIR photoinduced reaction by which 3·+ is cleanly converted to the vinylidenecyclopropane radical cation 4·+, a process that can be represented in terms of a single electron transfer from the allyl radical to the vinyl cation followed by allyl cation cyclization. The specificity of this photochemical reaction provides additional strong chemical evidence for the structure of 3·+. Theoretical calculations reveal the decisive role of vibronic coupling in shaping the potential energy surfaces on which the observed ring-opening reactions take place. Thus vibronic interaction in 1·+ mixes the ²A1′ ground state, characterized by its "non-bonding" 3a1 ′SOMO, with the ²E″ first excited state resulting in the destabilization of a lateral C-C bond and the initial formation of the methylenebicyclobutyl radical cation 5·+. The further rearrangement of 5·+ to 3·+ occurs via 2·+ and proceeds through two additional lateral C-C bond cleavages characterized by transition states of extremely low energy, thereby explaining the absence of identifiable intermediates along the reaction pathway. In these consecutive ring-opening rearrangements, the "non-bonding" bridgehead C-C bond in 1·+ is conserved and ultimately transformed into a normal bond characterized by a shorter C-C bond length. This work provides strong support for the Heilbronner-Wiberg interpretation of the vibrational structure in the photoelectron spectrum of 1 in terms of vibronic coupling. [ABSTRACT FROM AUTHOR]

A simple and highly efficient stereoselective total synthesis of dodoneine (), a naturally occurring bioactive 5,6-dihydro-2 H-pyran-2-one, was achieved. The synthesis involved Keck's asymmetric allylation, iodine-induced electrophilic cyclization, and Grubbs' catalyzed ring-closing metathesis as key steps. [ABSTRACT FROM AUTHOR]

Abstract: In the present work the stereocontrolled palladium-catalysed umpolung allylation of aldehydes is described. Allyl acetates are in situ transformed into the corresponding allyl boronates, which directly react with aldehydes. The question of stereocontrol is raised by employing (a) chiral boronating agents (reagent control) and by (b) utilising chiral aldehydes (substrate control). These studies reveal that the approach based on substrate control is superior to the former one with respect to yields and stereoselectivity. Remarkably, this umpolung protocol often yields the 4,5-syn products in high selectivity, which is unprecedented for direct crotylations. [ABSTRACT FROM AUTHOR]

Abstract: A protocol for the generation of allyl Grignard reagents via the catalytic activation of allyl halides is described herein. Subsequent nucleophilic addition to carbonyl derivatives provided the desired homo allylic alcohols in excellent yields (84–99%). Evidence suggests that titanocene dichloride catalyzes the formation of an allyl Grignard species which reacts solely with the carbonyl electrophile as evidenced by the complete absence of Würtz coupling. This methodology will have wide-ranging applicability in the generation of highly reactive organometallic reagents. [Copyright &y& Elsevier]

Abstract: (S)-4-Methyl-3,6-dihydro-2H-pyran-2-carbaldehyde (3), the common intermediate in the syntheses of the C17–C27 subunit of laulimalide (4) and (+)-faranal (5), the trail pheromone of the pharaoh ant, Monomorium pharaonis, were obtained via transformation of methyl 3-bromomethyl-3-butenoate (1) into allylstannane 2 and subsequent allylation of (benzyloxy)acetaldehyde (6) in accordance with the Keck procedure as the key steps. [Copyright &y& Elsevier]

An efficient and selective method for oxidation of glycosyl sulfides to the corresponding glycosyl sulfoxides with metalloporphyrins as catalysts and sodium hypochlorite as oxidant was achieved under mild conditions. High chemoselectivity and diastereomeric excesses were obtained. Both acid-labile protected groups and carbon-carbon double bonds of allyl groups tolerated under these conditions. [ABSTRACT FROM AUTHOR]

Abstract: We describe herein an extension of the halogenation of 1,2 or 1,3-diols via a cyclic thionocarbonate functionality by reaction with an allyl halide instead of methyl iodide, which is usually used. This investigation was successfully carried out under both conventional heating and microwave solvent-free conditions with some alditol, thioanhydroalditol, and aldose derivatives. [Copyright &y& Elsevier]

Acrylates 3 were synthesized following a known procedure using a Brønsted acid catalyst, and were converted into the O-allylated products 4 in high yields. The O-allylated products 4 undergo a Claisen rearrangement in refluxing DMF for 6-24 hours, affording compounds 5 with a-aryl quaternary carbon centers in high yields. [ABSTRACT FROM AUTHOR]

The highly selective synthesis of triene derivatives was achieved by a zirconocene-mediated three-component coupling reaction, and the trienes were efficiently subjected to 7-endo mode cyclization. The reaction of unsymmetrical zirconacyclopentadienes prepared from two different alkynes with N-bromosuccinimide (NBS) followed by treatment with allyl halides in the presence of CuCl afforded the corresponding heptatrienes in good yields. When the trienes reacted with an organolithium reagent, 7-endo mode cyclization occurred smoothly to give the corresponding cycloheptadiene. [ABSTRACT FROM AUTHOR]

Abstract: A facile method to obtain novel sucrose polymers is reported. These polymers were obtained by means of the Thiol-Ene photopolymerization technique. The sucrose was functionalized with allyl groups by etherification with allyl bromide and then photopolymerized by the step-growth mechanism with multifunctional thiols. The kinetics of photopolymerization were determined by optical pyrometry and Real-Time FT-IR. It was found that this photocurable system was highly reactive obtaining solid crosslinked polymers that displayed high uniformity in the crosslink density. A T g of 58°C was determined by means of DMA for the polymer derived from A2S and PETKMP. The prepared polymers displayed thermal stability up to 230°C. [Copyright &y& Elsevier]

One-pot borylation-allylation reactions of aldehydes and allylic alcohols were performed under various reaction conditions. The borylation of allylic alcohols was performed using a very efficient SCS palladium pincercomplex catalyst. The regioselectivity of the allylation depends on the applied solvent. The reaction in CHCI3 gave the linear allylic product; however, when MeOH was added to the reaction mixture, the branched allylic product was formed. [ABSTRACT FROM AUTHOR]