- Indium trichloride-catalyzed indium-mediated allylation of dihydropyrans and dihydrofurans in water
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A one-pot indium trichloride-catalyzed indium-mediated allylation of dihydropyrans and dihyfrofurans has been found to be feasible. This catalytic system afforded the allylated diols in moderate to high yields.
- Juan, Song,Hua, Zhi-Hao,Qi, Shen,Ji, Shun-Jun,Loh, Teck-Peng
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Read Online
- A general electron transfer reduction of lactones using SmI 2-H2O
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Herein we describe a strategy for the selective, electron transfer reduction of lactones of all ring sizes and topologies using SmI 2-H2O and a Lewis base to tune the redox properties of the complex. The current protocol permits instantaneous reduction of lactones to the corresponding diols in excellent yields, under mild reaction conditions and with useful chemoselectivity. We demonstrate the broad utility of this transformation through the reduction of complex lactones and sensitive drug-like molecules. Sequential electron transfer reactions and syntheses of deuterated diols are also described.
- Szostak, Michal,Collins, Karl D.,Fazakerley, Neal J.,Spain, Malcolm,Procter, David J.
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supporting information; experimental part
p. 5820 - 5824
(2012/08/28)
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- One-pot sequential deoximation and allylation reactions of aldoximes in aqueous solution
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A simple procedure has been developed for conducting tin-mediated deoximation and allylation reactions of aldoximes in water to form homoallylic alcohols. Employing the new conditions, various homoallylic alcohols were produced in good to excellent yields
- Lin, Mei-Huey,Lin, Long-Zhi,Chuang, Tsung-Hsun,Liu, Han-Jun
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experimental part
p. 2630 - 2635
(2012/04/23)
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- FeCl3-catalysed Zn-mediated allylation of cyclic enol ethers in water
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A mild and environment-friendly Zn-mediated allylation of dihydrofuran and dihydropyran catalysed by iron(III) chloride in water has been developed. [Figure not available: see fulltext.]
- Chakraborty,Roy
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supporting information; experimental part
p. 509 - 512
(2012/08/07)
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- Evaluation of the key aroma compounds in beef and pork vegetable gravies a la chef by stable isotope dilution assays and aroma recombination experiments
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Although the aroma compounds of meat processed as such have been studied previously, data on complete homemade dishes containing beef and pork meat were scarcely studied. Recently, 38 odor-active compounds were characterized in beef and pork vegetable gravies using GC-olfactometry. In the present investigation, the most odor-active compounds were quantitated in a freshly prepared stewed beef vegetable gravy (BVG) as well as a stewed pork vegetable gravy (PVG) by means of stable isotope dilution assays. Calculation of odor activity values (OAVs; ratio of concentration to odor threshold) revealed 3-mercapto-2- methylpentan-1-ol, (E,E)-2,4-decadienal, (E,Z)-2,6-nonadienal, (E)-2-decenal, (E)-2-undecanal, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone as the most potent odorants in both gravies. However, significantly different OAVs were found for 12-methyltridecanal, which was much higher in the BVG, whereas (E,Z)-2,4-decadienal showed a clearly higher OAV in the PVG. Aroma recombination experiments performed on the basis of the actual concentrations of the odorants in both gravies revealed a good similarity of the aromas of both model mixtures containing all odorants with OAVs > 1 with those of the original gravies.
- Christlbauer, Monika,Schieberle, Peter
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experimental part
p. 13122 - 13130
(2012/03/22)
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- Tin mediated allylation reactions of enol ethers in water
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Under tin-mediated Barbier-type reaction conditions, hydration of enol ethers takes place to form aldehydes that undergo allylation reactions. By using this process, various homoallylic alcohols and 2-halohomoallylic alcohols are produced in good to excel
- Lin, Mei-Huey,Hung, Shiang-Fu,Lin, Long-Zhi,Tsai, Wen-Shing,Chuang, Tsung-Hsun
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supporting information; experimental part
p. 332 - 335
(2011/03/23)
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- Design and synthesis of novel fluoro amino acids: synthons for potent macrocyclic HCV NS3 protease inhibitors
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The Hepatitis C Virus (HCV) is a major health hazard and its infection is a leading cause of chronic liver disease world wide. In our efforts toward the discovery of a back up to our first clinical candidate, Boceprevir (SCH 503034), we approached the depeptidization of the molecule through macrocyclization. Herein we report the design and synthesis of fluoro amino acids with desired stereochemistry required for the synthesis of macrocyclic inhibitors with fluorine at various positions of the aliphatic chain. Biological activities of representative examples are also reported.
- Nair, Latha G.,Bogen, Stephane,Bennett, Frank,Chen, Kevin,Vibulbhan, Bancha,Huang, Yuhua,Yang, Weing,Doll, Ronald J.,Shih,Njoroge, F. George
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supporting information; experimental part
p. 3057 - 3061
(2010/08/05)
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- Pd-catalyzed nucleophilic allylic alkylation of aliphatic aldehydes by the use of allyl alcohols
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Under catalysis of Pd(OAc)2-(P-n-Bu)3, Et 2Zn promotes a variety of allyl alcohols to undergo nucleophilic allylation of aliphatic aldehydes and ketones at room temperature and provides homoallyl alcohols in 60-90 and ca. 60% isolated yield, respectively. The reaction is irreversible and kinetically controlled, and unique regio- and stereoselectivities observed for the allylation with unsymmetrically substituted allyl alcohols are discussed.
- Kimura, Masanari,Shimizu, Masamichi,Tanaka, Shuji,Tamaru, Yoshinao
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p. 3709 - 3718
(2007/10/03)
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- Use of allyl, 2-tetrahydrofuryl, and 2-tetrahydropyranyl ethers as useful C3-, C4-, and C5-carbon sources: Palladium-catalyzed allylation of aldehydes
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Palladium-diethylzinc or palladium-triethylborane catalytically promotes self-allylation of 2-(allyloxy)tetrahydrofurans, 2-(allyloxy)tetrahydropyrans, and their hydroxy derivatives on the rings (ribose, glucose, mannose, deoxyribose, deoxyglucose). All the reactions proceed at room temperature and provide polyhydroxyl products, sharing a structural motif of a homoallyl alcohol, in good to excellent yields with high levels of stereoselectivity. Useful Crunit elongation, which makes the best use of an allyl ether as a protecting group and a nucleophilic allylation agent, is demonstrated. Mechanisms for the umpolung reaction (of an allyl ether into an allylic anion) and stereoselectivity associated with allylation of aldehydes are discussed.
- Shimizu, Masamichi,Kimura, Masanari,Tamaru, Yoshinao
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p. 6629 - 6642
(2007/10/03)
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- Formation of manganese-alkyne complexes mediated by trialkylmanganates and their application
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Treatment of dodec-6-yne with triallylmanganate in the presence of 1,3,5-trimethylbenzene provides (Z)-dodec-6-ene. An addition of D2O before quenching the reaction affords the corresponding dideuterated alkene. The result suggests the existence of the manganese-alkyne complex as an intermediate. Treatment of methyl propargyl ethers as alkynes with tributylmanganate generates propargylmanganese species. The reaction of non-2-ynyl tetrahydropyran-2-yl ether with tributylmanganate provides tetradec-7-yn-1,5-diol and 6-hexylocta-6,7-dien-1,5-diol.
- Nishikawa, Toshihiro,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 9661 - 9668
(2007/10/03)
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- Pd-catalyzed nucleophilic alkylation of aliphatic aldehydes with allyl alcohols: Allyl, 2-tetrahydrofuryl, and 2-tetrahydropyranyl ethers as useful C3, C4, and C5 sources
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A combination of Pd° and Et2Zn generates an allyl anion species from allyl alcohols which can be used for the allylation of aliphatic aldehydes to provide homoallyl alcohols in good yields (see scheme). The reaction proceeds at room temperature in poor coordination solvents, such as a mixture of toluene and n-hexane.
- Kimura, Masanari,Shimizu, Masamichi,Shibata, Kazufumi,Tazoe, Minoru,Tamaru, Yoshinao
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p. 3392 - 3395
(2007/10/03)
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- Transformation of tetrahydropyranyl ether of allylic alcohol into 7- octene-1,5-diol by means of trialkylmanganate
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Treatment of tetrahydropyranyl (or tetrahydrofuranyl) ether of allylic alcohol with tributylmanganate provided 7-octene-l,5-diol (or 6-hepten-1,4- diol) in good yields. The reaction of propargylic tetrahydropyranyl ether with tributylmanganate is also described.
- Nishikawa, Toshihiro,Nakamura, Tomoaki,Kakiya, Hirotada,Yorimitsu, Hideki,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 6613 - 6616
(2007/10/03)
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- ORGANOMETALLIC REACTIONS IN AQUEOUS MEDIA WITH INDIUM
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Allylation reactions of aldehydes and ketones occurred smoothly with indium metal in aqueous media.Compared to similar reactions with zinc and tin, the reaction with indium proceeds without the need of any promoter.The reaction can be extended to the synthesis of 2-methylene-γ-lactone 6 via the condensation of carbonyl compounds with 2-bromomethylacrylate 4.
- Li, C. J.,Chan, T. H.
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p. 7017 - 7020
(2007/10/02)
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- A Grignard-Type Addition of Allyl Unit to Aldehydes by Using Bismuth and Bismuth Salt
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In the presence of metallic bismuth, bismuth(III) chloride-metallic zinc, or bismuth(III) chloride-metallic iron, allylic halides have been found to react with aldehydes under mild conditions to give the corresponding homoallylic alcohols in high yields with high chemo-, regio-, and stereoselectivity.Allylic halides have been also found to react with aldehydes at room temperature in tetrahydrofuran-water by using bismuth(III) chloride-metallic aluminium to afford the expected homoallylic alcohols in high yields.
- Wada, Makoto,Ohki, Hidenori,Akiba, Kin-ya
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p. 1738 - 1747
(2007/10/02)
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- SELECTIVE ALLYLATION OF CARBONYL COMPOUNDS IN AQUEOUS MEDIA
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The use of aqueous neutral media leads to excellent yelds of homoallylic alcohols from reactions of allyl halides with carbonyl compounds in the presence of tin or zinc.The stereochemical course and range of application of this reaction have been investigated.
- Einhorn, Cathy,Luche, Jean-Louis
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p. 177 - 184
(2007/10/02)
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- CARBON-CARBON BOND FORMATION WITH BISMUTH SALT. A CHEMOSELECTIVE GRIGNARD-TYPE ADDITION OF ALLYL UNIT TO ALDEHYDES
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In the presence of bismuth(III) chloride-metallic zinc or bismuth(III) chloride-metallic iron, allylic halides were found to react with aldehydes under mild conditions to give the corresponding homoallylic alcohols in high yields with high chemoselectivity.
- Wada, Makoto,Ohki, Hidenori,Akiba, Kin-ya
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p. 4771 - 4774
(2007/10/02)
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