- Stereoselective synthesis of chiral δ-lactonesviaan engineered carbonyl reductase
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A carbonyl reductase variant,SmCRM5, fromSerratia marcescenswas obtained through structure-guided directed evolution. The variant showed improved specific activity (U mg?1) towards most of the 16 tested substrates and gave high stereoselectivities of up to 99% in the asymmetric synthesis of 13 γ-/δ-lactones. In particular, SmCRM5showed a 13.8-fold higher specific activity towards the model substrate,i.e., 5-oxodecanoic acid, and gave (R)-δ-decalactone in 99% ee with a space-time yield (STY) of 301 g L?1d?1. The preparative synthesis of six δ-lactones in high yields and with high enantiopurities showed the feasibility of the biocatalytic synthesis of these high-value-added chemicals, providing a cost-effective and green alternative to noble-metal catalysis.
- Wang, Tao,Zhang, Xiao-Yan,Zheng, Yu-Cong,Bai, Yun-Peng
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p. 10584 - 10587
(2021/10/19)
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- MODIFIED AMINE LIPIDS
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The disclosure provides ionizable amine lipids and salts thereof (e.g., pharmaceutically acceptable salts thereof) useful for the delivery of biologically active agents, for example delivering biologically active agents to cells to prepare engineered cells. The ionizable amine lipids disclosed herein are useful as ionizable lipids in the formulation of lipid nanoparticle-based compositions.
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- Efficient Stereoselective Synthesis of Structurally Diverse γ- and δ-Lactones Using an Engineered Carbonyl Reductase
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Structurally diverse γ- and δ-lactones were efficiently synthesized stereoselectively using an engineered carbonyl reductase from Serratia marcescens (SmCRV4). SmCRV4 exhibited improved activity (up to 500-fold) and thermostability toward 14 γ-/δ-keto acids and esters, compared with the wild-type enzyme, with 110-fold enhancement in catalytic efficiency (kcat/Km) toward methyl 4-oxodecanoate. The preparative synthesis of alkyl and aromatic γ- and δ-lactones with 95 %–>99 % ee and 78 %–90 % yields was demonstrated. The highest space-time yield, 1175 g L?1 d?1, was achieved for (R)-γ-decalactone.
- Chen, Meng,Zhang, Xiao-Yan,Xing, Chen-Guang,Zhang, Chao,Zheng, Yu-Cong,Pan, Jiang,Xu, Jian-He,Bai, Yun-Peng
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p. 2600 - 2606
(2019/05/21)
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- Enantioselective organocatalysis-based synthesis of 3-hydroxy fatty acids and fatty γ-lactones
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3-Hydroxy fatty acids have attracted the interest of researchers, since some of them may interact with free fatty acid receptors more effectively than their non-hydroxylated counterparts and their determination in plasma provides diagnostic information regarding mitochondrial deficiency. We present here the development of a convenient and general methodology for the asymmetric synthesis of 3-hydroxy fatty acids. The enantioselective organocatalytic synthesis of terminal epoxides, starting from long chain aldehydes, is the key-step of our methodology, followed by ring opening with vinylmagnesium bromide. Ozonolysis and subsequent oxidation leads to the target products. MacMillan’s third generation imidazolidinone organocatalyst has been employed for the epoxide formation, ensuring products in high enantiomeric purity. Furthermore, a route for the incorporation of deuterium on the carbon atom carrying the hydroxy group was developed allowing the synthesis of deuterated derivatives, which may be useful in biological studies and in mass spectrometry studies. In addition, the synthesis of fatty γ-lactones, corresponding to 4-hydroxy fatty acids, was also explored.
- Bourboula, Asimina,Limnios, Dimitris,Kokotou, Maroula G.,Mountanea, Olga G.,Kokotos, George
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- Lewis Base/Br?nsted Acid Co-Catalyzed Asymmetric Thiolation of Alkenes with Acid-Controlled Divergent Regioselectivity
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A divergent strategy for the facile preparation of various enantioenriched phenylthio-substituted lactones was developed based on Lewis base/Br?nsted acid co-catalyzed thiolation of homoallylic acids. The acid-controlled regiodivergent cyclization (6-endo vs. 5-exo) and acid-mediated stereoselective rearrangement of phenylthio-substituted lactones were explored. Experimental and computational studies were performed to clarify the origins of the regioselectivity and enantioselectivity. The calculation results suggest that C?O and C?S bond formation might occur simultaneously, without formation of a commonly supposed catalyst-coordinated thiiranium ion intermediate and the potential π–π stacking between substrate and SPh as an important factor in the enantio-determining step. Finally, this methodology was applied in the rapid syntheses of the bioactive natural products (+)-ricciocarpin A and (R)-dodecan-4-olide.
- Luo, Hui-Yun,Dong, Jia-Wei,Xie, Yu-Yang,Song, Xu-Feng,Zhu, Deng,Ding, Tongmei,Liu, Yuanyuan,Chen, Zhi-Min
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supporting information
p. 15411 - 15418
(2019/11/14)
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- Diastereo- and Enantioselective Synthesis of (E)-δ-Boryl-Substituted anti-Homoallylic Alcohols in Two Steps from Terminal Alkynes
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We report the highly diastereo- and enantioselective preparation of (E)-δ-boryl-substituted anti-homoallylic alcohols in two steps from terminal alkynes. This method consists of a cobalt(II)-catalyzed 1,1-diboration reaction of terminal alkynes with B2pin2 and a palladium(I)-mediated asymmetric allylation reaction of the resulting 1,1-di(boryl)alk-1-enes with aldehydes in the presence of a chiral phosphoric acid. Propyne, which is produced as the byproduct during petroleum refining, could be used as the starting material to construct homoallylic alcohols that are otherwise difficult to synthesize with high stereocontrol.
- Miura, Tomoya,Oku, Naoki,Murakami, Masahiro
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supporting information
p. 14620 - 14624
(2019/09/06)
-
- Synthesis method of paederus fuscipes sex pheromone
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The invention belongs to the technical field of chemical synthesis and in particular relates to a synthesis method of paederus fuscipes sex pheromone. An R configuration optical isomer of the paederusfuscipes sex pheromone has the following structure: the formula is shown in the description; the synthesis method of the R configuration optical isomer of the paederus fuscipes sex pheromone comprises the following steps: enabling nonanal and methyl propiolate to react, so as to obtain chiral alcohol ester; enabling the chiral alcohol ester to react, so as to obtain the paederus fuscipes sex pheromone. The paederus fuscipes sex pheromone prepared by the synthesis method has high optical activity; a synthesis route is simple and the cost is low; a prepared paederus fuscipes sex pheromone lureproduct can have a protection effect on field workers and resident in regions at which paederus fuscipes usually occurs, and has good commercial application value.
- -
-
Paragraph 0032; 0033
(2018/10/26)
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- Asymmetric bioreduction of keto groups of 4- and 5-Oxodecanoic acids/esters with a new carbonyl reductase
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A novel carbonyl reductase from Serratia marcescens, SmCR, was successfully cloned and overexpressed in Escherichia coli. SmCR could catalyze the asymmetric reduction of long-chain keto acids/esters containing remote carbonyl groups, such as 4-oxo- and 5-oxodecanoic acids, yielding chiral γ- and δ-decalactones with high enantiopurity (up to 99% ee). This is the first report of enzymatic synthesis of (R)-γ- and (R)-δ-decalactones starting from γ-, δ-keto acids using free enzymes.
- Zhang, Chao,Pan, Jiang,Li, Chun-Xiu,Bai, Yun-Peng,Xu, Jian-He
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-
- Chiral Surfactant-Type Catalyst: Enantioselective Reduction of Long-Chain Aliphatic Ketoesters in Water
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A series of amphiphilic ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neat water. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and ε-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst 2. The CH/π interaction and the strong hydrophobic interaction of long aliphatic chains between the catalyst and the substrate in the metallomicelle core played a key role in the catalytic transition state. Synergistic effects between the metal-catalyzed site and the hydrophobic microenvironment of the core in the micelle contributed to high stereoselectivity. (Chemical Equation Presented).
- Lin, Zechao,Li, Jiahong,Huang, Qingfei,Huang, Qiuya,Wang, Qiwei,Tang, Lei,Gong, Deying,Yang, Jun,Zhu, Jin,Deng, Jingen
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p. 4419 - 4429
(2015/05/13)
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- Enantioselective transesterification of (±)1phenylundecan-3-ol catalyzed by the lipase from Burkholderia cepacia
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Enantiomerically enriched (R) and (S)-1-phenylundecan-3-ols were obtained by kinetic resolution of the racemate with vinyl acetate in ButOMe at 20 °C using the lipase from Burkhold eria cepacia. The absolute configuration of the enantiomers was
- Vlasyuk,Voblikova,Gamalevich,Serebryakov
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p. 2041 - 2045
(2014/07/07)
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- γ-substituted butanolides from cyclopropane hemimalonates: An expedient synthesis of natural (R)-dodecan-4-olide
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Exploration into the reactivity of donor-acceptor cyclopropane hemimalonates has led to the facile synthesis of γ-substituted butanolides. Under microwave irradiation, cyclopropane hemimalonates undergo rapid conversion to butanolides in the presence of i
- Grover, Huck K.,Emmett, Michael R.,Kerr, Michael A.
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supporting information
p. 4838 - 4841
(2013/10/08)
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- Synthesis of optically active heterocyclic compounds via deracemization of 1,2-diol monotosylate derivatives bearing a long aliphatic chain by a combination of enzymatic hydrolysis with Mitsunobu inversion
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We have succeeded in accomplishing the deracemization of (±)-2-acetoxydecyl and (±)-acetoxy-6-benzyloxyhexyl tosylates, which have a long substituent, via an enzyme-mediated enantioselective hydrolysis with a Mitsunobu inversion using polymer-supported triphenylphosphine to afford the corresponding (S)-enantiomer. Enantiomerically pure (S)- and (R)-γ-dodecalactones, a fruit flavor, were synthesized from (S)-2-acetoxydecyl tosylate as the mutual starting material. The poisonous alkaloid (S)-coniine was also synthesized using enantiomerically pure allyl amine as the key intermediate derived from (S)-acetoxy-6-benzyloxyhexyl tosylate.
- Matsumoto, Kazutsugu,Usuda, Kazumasa,Okabe, Hirokazu,Hashimoto, Manabu,Shimada, Yasutaka
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p. 108 - 115
(2013/04/23)
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- The absolute configuration of (+)- And (-)-1-phenylundec-4-yn-3-ols. Synthesis of (R)-4-dodecanolide, a component of the defensive secretion of rove beetle Bledius mandibullaris
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Hydrogenation of the triple bond of (+)-1-phenylundec-4-yn-3-ol (obtained from (+)[η6 (3-hydroxyundec-4-yn-1-yl)benzene]chromium tricarbonyl) with the NaBH4-NiCl2?6H2O reagent system in MeOH leads to (-)1-phenylundecan-3-ol. Ozonolysis of the phenyl ring in the corresponding acetate gives (R)-(-)acetoxydodecanoic acid, lactonization of which leads to the known (R)-(+)-4dodecanolide. The starting (+)-1phenylundec-4-yn-3-ol was thus shown to have the Sconfiguration.
- Vlasyuk,Voblikova,Gamalevich,Serebryakov
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p. 2032 - 2036
(2014/07/07)
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- Cyclodextrin-based ionic liquids as enantioselective stationary phases in gas chromatography
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New permethylated mono-6-deoxy-6-pyridin-1-ium and mono-6-deoxy-6-(1-vinyl- 1H-imidazol-3-ium)-α- and -β-cyclodextrin trifluoromethanesulfonate ionic liquids were synthesized from the corresponding permethylated mono-6-hydroxycyclodextrins in a one-pot reaction and solvent-free procedure. Regioselective transformation of native α- and β-cyclodextrins with the use of a bulky tert-butyldiphenylsilyl protecting group afforded the desired 6-monosubstituted permethylated cyclodextrin derivatives in moderate yields. The new ionic liquids were tested as stationary phases in capillary GC columns towards chiral discrimination in enantio-GC analysis of racemic mixtures. The permethylated 6-deoxy-6-pyridin-1-ium-α-cyclodextrin trifluoromethanesulfonate displayed good enantiomeric separations for some racemic esters and lactones, as well as epoxides. In particular, for both the racemic whiskey lactone and the high boiling point menthyl laurate, not successfully separated in a commercial cyclodextrin phase, the enantiomeric separations were achieved isothermally at 140 °C. In phase: Permethylated mono-6-hydroxy-α- and -β-cyclodextrins react with pyridine or 1-vinylimidazole in the presence of triflic anhydride in a solvent-free procedure to yield new roomerature ionic liquids (ILs). These ILs have been used as stationary phases in gas chromatography; enantiomeric separations are achieved (see figure for whiskey lactone) with permethylated mono-6-deoxy-6-(pyridin-1-ium)-α-cyclodextrin trifluoromethanesulfonate. Copyright
- Costa, Nuno,Matos, Sara,Da Silva, Marco D. R. Gomes,Pereira, M. Manuela A.
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p. 1466 - 1474
(2014/01/06)
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- Combination of novozym 435-catalyzed hydrolysis and mitsunobu reaction for production of (r)γ-lactones
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Chiral-lactones of both enantiomers were synthesized with more than 90% optical purities. The key step was Novozym 435-catalyzed hydrolysis of racemic N-benzyl-4-acetoxyalkylamides. Additionally, because (R)-γ-lactones are predominant in apricot, mango, peach, passion fruit, and strawberry, synthesis was attempted using only one enantiomer selectively. The (R)-enantimer was synthesized with more than 80% total yield and more than 90% optical purity by a combination of Novozym 435-catalyzed hydrolysis and the Mitsunobu reaction. Copyright
- Shimotori, Yasutaka,Miyakoshi, Tetsuo
-
experimental part
p. 1607 - 1613
(2010/06/21)
-
- Efficient and flexible synthesis of chiral γ- And δ-lactones
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An efficient and highly flexible synthesis for chiral γ- and δ-lactones with high enantiomeric purity is described (>99% ee and 57-87% overall yield). The protocol involves alkylation of chiral 1,2-oxiranes with terminally unsaturated Grignard reagents. Subsequent oxidative degradation (OsO4-Oxone) of the terminal double bond from chiral alk-1-en-5-ols and alk-1-en-6-ols affords 4- or 5-hydroxy acids and γ- and δ-lactones after acidic workup. The flexibility and efficiency of the protocol is illustrated by the synthesis of several alkanolides and alkenolides, hydroxy fatty acids and dihydroisocoumarins. The Royal Society of Chemistry 2008.
- Habel, Andreas,Boland, Wilhelm
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experimental part
p. 1601 - 1604
(2008/10/09)
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- Titanocene-catalyzed regiodivergent epoxide openings
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The first regiodivergent opening of unbiased epoxides providing the ring-opened products in high enantiomeric excess from racemic and exceptionally high enantiomeric excess from enantioenriched substrates in a double asymmetric process has been devised. It constitutes a more general case of the very important enantioselective openings of meso-epoxides. Copyright
- Gansaeuer, Andreas,Fan, Chun-An,Keller, Florian,Keil, Jutta
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p. 3484 - 3485
(2008/01/01)
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- Total synthesis of insect pheromones (R)-4-dodecanolide and (S)-5-hexadecanolide
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The asymmetric total synthesis of naturally occurring insect pheromones, (R)-4-dodecanolide and (S)-5-hexadecanolide has been achieved in a simple and efficient way with high yields. Georg Thieme Verlag Stuttgart.
- Sabitha, Gowravaram,Reddy, E. Venkata,Yadagiri,Yadav
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p. 3270 - 3274
(2008/09/17)
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- Ligand effects in aluminium-catalyzed asymmetric Baeyer-Villiger reactions
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Asymmetric Baeyer-Villiger oxidations of racemic and prochiral cyclobutanones can be performed with chiral aluminium-based Lewis acids resulting in products with good enantioselectivities in high yields. By employing substituted BINOL derivatives as ligan
- Frison, Jean-Cédric,Palazzi, Chiara,Bolm, Carsten
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p. 6700 - 6706
(2007/10/03)
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- Lactone synthesis via biotransformations of γ-hydroxyamides
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An enzyme was expressed in E. coli from a cloned amidase gene. When characterized, it was more enantioselective than commercial amidases. Three pheromones were made. An enzyme was expressed in Escherichia coli from a cloned amidase gene. When characterized, it was more enantioselective than commercial amidases. Three pheromones were made using this biotransformation chemistry.
- Taylor, Stephen K.,Arnold, Carrie R.,Gerds, Aaron T.,Ide, Nathan D.,Law, Keri M.,Kling, Dale L.,Pridgeon, Matthew G.,Simons, Lloyd J.,Vyvyan, James R.,Yamaoka, Jennifer S.,Liao, Min-Ken,Goyne, Thomas E.
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p. 3819 - 3821
(2007/10/03)
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- Process-scale preparation of enantiomerically pure γ-lactones by asymmetric hydrogenation of γ-ketoesters and comparative tests of the sensory properties of some antipodes
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A reliable methodology, applicable on a process-scale level, for producing enantiomerically pure chiral γ-lactones by enantioselective hydrogenation of γ-ketoesters, followed by cyclisation of the resulting γ-hydroxyesters, has been developed. The multi-step procedure was transformed into a one-pot reaction. A very efficient chiral Ru-complex, based on the biheteroaromatic diphosphine ligand tetraMe-BITIOP, was developed as a catalyst, capable of coupling fast kinetics with high stereoselection levels. Its structure was fully elucidated through 31P NMR, EPR and X-ray single-crystal analyses. The optimal experimental conditions are as follows: hydrogen pressure=30psi, S/C ratio=2000, 30% in weight substrate concentration. Yields are quantitative and enantiomeric excesses in the range 98-99.9%. Sensorial tests on the antipodes of two γ-lactones demonstrated the very different properties of the enantiomers.
- Benincori, Tiziana,Rizzo, Simona,Pilati, Tullio,Ponti, Alessandro,Sada, Mara,Pagliarini, Ella,Ratti, Simona,Giuseppe, Celentano,De Ferra, Lorenzo,Sannicolo, Franco
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p. 2289 - 2297
(2007/10/03)
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- Facile synthesis of optically active γ-lactones via lipase-catalyzed reaction of 4-substituted 4-hydroxybutyramides
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Lipase-catalyzed transesterification of racemic 4-substituted 4- hydroxybutyramides with succinic anhydride proceeded enantioselectively to afford (S)-succinic acid monoester and unreacted (R)-4-hydroxybutyramide derivative, which were separated easily by
- Matsumura, Yasufumi,Endo, Teruko,Chiba, Mitsuo,Fukawa, Hidemichi,Terao, Yoshiyasu
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p. 304 - 305
(2007/10/03)
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- A novel tandem Michael addition/Meerwein-Ponndorf-Verley reduction: Asymmetric reduction of acyclic α,β-unsaturated ketones using a chiral mercapto alcohol
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The introduction of a thiol group into a chiral alcohol reagent for asymmetric Meerwein-Ponndorf-Verley (MPV) reductions allows asymmetric reduction of α,β-unsaturated ketones to secondary alcohols and allylic alcohols via a novel tandem Michael addition/MPV reduction. The reaction of acyclic α,β-unsaturated ketones 1 and an optically active 1,3-mercapto alcohol (-)-2 using dimethylaluminum chloride afforded the MPV reduction products 3 diastereoselectively in very high yields (up to 96%). Mechanistic studies elucidated (1) the structure of the chelation complex D with (-)-2 and Me2AlCl, (2) an asymmetric 1,7-hydride shift (intramolecular MPV reduction), and (3) dynamic kinetic resolution via reversible Michael addition. Subsequent reductive desulfurization of the MPV products 3 with a modified Raney nickel system led to the highly enantioselective reduction of α,β-unsaturated ketones to saturated secondary alcohols in 96-98% ee. β-Elimination of the corresponding sulfoxides gave the allylic alcohols in 86-98% ee. Applications to the asymmetric reduction of a synthetic intermediate 1m of prostaglandins and to a new asymmetric synthesis of the (+)-Rove beetle pheromone 11 are described.
- Node, Manabu,Nishide, Kiyoharu,Shigeta, Yukihiro,Shiraki, Hiroaki,Obata, Kenichi
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p. 1927 - 1936
(2007/10/03)
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- Syntheses of rac- and optically active 2-alkyl-γ-butyrolactones and 2- alkyl-cyclobutanones
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γ-Butyrolactones have been produced in good yield from alkylidene cyclopropanes, as racemates or as an enantiomerically enriched mixture of stereoisomers (e.e.>60%) depending upon the method used. Optically active cyclobutanones which are intermediate in the process have been in some cases isolated. We show the limitations of a competitive method previously described and point out its weak step.
- Krief, Alain,Ronvaux, Alain,Tuch, Arounarith
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p. 6903 - 6908
(2007/10/03)
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- Catalytic enantioselective synthesis of 2-alkylcyclobutanones and 4-alkyl-γ-butyrolactones from alkylidenecyclopropanes and the Sharpless AD-mix reagent
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Reaction of AD-mix with alkylidenecyclopropanes allows the synthesis of optically active 2-alkylcyclobutanones and 4-alkyl-γ-butyrolactones after stepwise pinacolic rearrangement and Beyer-Villiger oxidation.
- Krief, Alain,Ronvaux, Alain,Tuch, Arounarith
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p. 699 - 702
(2007/10/03)
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- Synthesis of Optically Active Butenolides and γ-Lactones by the Sharpless Asymmetric Dihydroxylation of β,γ-Unsaturated Carboxylic Esters
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Keywords: asymmetric synthesis; butenolides; dihydroxylations; furanones; lactones
- Harcken, Christian,Brueckner, Reinhard
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p. 2750 - 2752
(2007/10/03)
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- Synthesis and absolute stereochemistry of Hagen's-Gland lactones in some parasitic wasps (Hymenoptera:Braconidae)
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Efficient syntheses and enantioselective gas chromatography have confirmed the structures and established the absolute stcreochemistry of some novel bicyclic lactones (tetrahydrofurofuranones) in species of parasitic wasps (Hymenoptera:Braconidae). The co-occurring γ-lactones, octan-4-olide and dodecan-4-olide, have the (R)-configuation.
- Paddon-Jones, Gregory C.,Moore, Christopher J.,Brecknell, Douglas J.,Koenig, Wilfried A.,Kitching, William
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p. 3479 - 3482
(2007/10/03)
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- Biotransformation of Oleic Acid to Optically Active γ-Dodecalactone
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We contemplated the formation of γ-dodecalactone through microbial conversion consisting of two steps, the first for oxidizing oleic acid into 10-hydroxystearic acid and the second for the formation of γ-dodecalactone from the hydroxy acid.Microorganisms were screened for production of 10-hydroxystearic acid from oleic acid.A bacterium which could produce the hydroxy acid with a transformation yield of 61.5percent at a concentration of 5percent oleic acid was isolated.The hydroxy acid was found to be biotransformed to γ-dodecalactone by baker's yeast.The enantiomeric composition of the biosynthetic γ-dodecalactone was estimated to be the (R)- configuration and the optical purity of the lactone was estimated to be 87.6percent e.e.The biotransformation yield from oleic acid to γ-dodecalactone was 22.5percent.
- Gocho, Shinobu,Tabogami, Nariyuki,Inagaki, Masao,Kawabata, Choko,Komai, Tuyosi
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p. 1571 - 1572
(2007/10/02)
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- 3-(Alkylthio)-1,2-bis(siloxy)-3-butenes as efficient chirality transferred building blocks
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In the presence of Me2AlCl, reactions of the title compounds with a variety of aldehydes proceeded with high efficacy of chirality transfer to give the corresponding optically pure ene adducts, which could be converted to the γ-lactones, e.g.,
- Masuya, Keiichi,Tanino, Keiji,Kuwajima, Isao
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p. 7965 - 7968
(2007/10/02)
-
- Ring opening of 2,3-epoxy 1-tosylates to halohydrins and subsequent elaboration to asymmetrical alcohols
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2,3-epoxy alcohols-1-tosylates are regio and chemoselectively opened to the corresponding 3-halohydrins (I, Br, Cl): the reduction of the iodohydrins to the monoprotected diols and subsequent standard coupling of the tosyl group leads to a straightforward synthesis of optically active naturally occurring pheromones
- Federici,Federici, Chiara,Righi,Righi, Giuliana,Rossi,Rossi, Leucio,Bonini,Bonini, Carlo,Chiummiento,Chiummiento, Lucia,Funicello,Funicello, Maria
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p. 797 - 800
(2007/10/02)
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- Dihydro- and Tetrahydrofuran Building Blocks from 1,4:3,6-Dianhydromannitol. 1. Synthesis of (1S,5R,7R)-endo-(-)- and (1S,5R,7S)-(-)-exo-Brevicomin and (R)-(+)-Dodecanolide
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The eliminative ring fission of iodides derived from 1,4:3,6-dianhydromannitol has been exploited for preparing three enantiomerically pure species, 1-3, which feature a di- or tetrahydrofuran moiety and one or two stereogenic centers.These species are extremely versatile building blocks for the construction of natural products.Their potential was demonstrated by the synthesis of the title insect pheromones.
- Cere, Vanda,Mazzini, Claudio,Paolucci, Claudio,Pollicino, Salvatore,Fava, Antonino
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p. 4567 - 4571
(2007/10/02)
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- Stereoselective Acetalization of 1,3-Alkanediols by l-Menthone: Application to the Resolution of Racemic 1,3-Alkanediols and to the Determination of the Absolute Configuration of Enantiomeric 1,3-Alkanediols
-
A general and reliable method for the resolution of racemic 1,3-alkanediols, which involves their conversion into diastereomeric spiroacetals derived from l-menthone, is described.Thus, the reaction of the bis-O-trimethylsilyl derivatives of racemic 1,3-alkanediols with l-menthone in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate affords the diastereomeric spiroacetals 3 and 4.The two can be readily separated by silica gel column chromatography.Hydrolysis of each diastereomer under acidic conditions liberates the corresponding enantiomerically pure diol.An empirically derived correlation of configuration and 1H NMR chemical shifts for spiroacetals 3 and 4 has been developed which is rationalized based on long-range effects due to the magnetic anisotropy inherent to the menthane ring in a rigid spiroacetal conformation.The method described here should be widely applicable to the determination of the absolute configuration of various 1,3-alkanediols.
- Harada, Toshiro,Kurokawa, Hideaki,Kagamihara, Yasuhiro,Tanaka, Sachi,Inoue, Atsushi,Oku, Akira
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p. 1412 - 1421
(2007/10/02)
-
- Lipase-catalyzed Transesterification in organic Solvents: Preparation and Enantiodifferentiation of optically enriched 4(5)-alkylated 1,4(1,5)-olides
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Porcine pancreatic lipase (PPL) catalyzed intramolecular transesterification of n-propyl esters of 4(5)-hydroxyalkanoic acids (C5-C12) in diethyl ether (20 deg C) yielded (S)-4-alkylated 1,4-olides of high optical purity (ee > 80percent) and optically pure (R)-4-hydroxyalkanoic-n-propylesters, but exhibited low enantioselectivity for (S)-5-alkylated 1,5-olides (ee=10-20percent).The chiral analysis of 4(5)-hydroxyalkanoic esters was performed by HRGC and HPLC after their derivatization with (R)-(+)-1-phenylethylisocyanate, (S)-O-acetyllactic acid chloride, and (R)-(+)-α-methoxy-α-trifluoromethylphenylacetic acid chloride.The enantiodifferentiation of 1,4(1,5)-olides was achieved by HPLC on a chiral (ChiraSpher) using an on-line optical rotation detector (ChiraMonitor).
- Huffer, Manfred,Schreier, Peter
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p. 1157 - 1164
(2007/10/02)
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- Stereochemistry of the Microbial Generation of δ-Decanolide, γ-Dodecanolide, and γ-Nonanolide from C18 13-Hydroxy, C18 10-Hydroxy, and C19 14-Hydroxy Unsaturated Fatty Acids
-
(S)-δ-Decanolide (4) was isolated from cultures of Cladosporium suaveolens after the microorganism was fed either (S)- or (R,S)-coriolic acid (1).Feeding (R,S)-10-hydroxyoctadec-(8E)-enoic acid (2) to Yarrowia lipolytica produced (S)-γ-dodecanolide.When (S)-homocoriolic acid (3) was fed to C. suaveolens, γ-nonalide slightly enriched in the S enantiomer was produced.At some stage in the biodegradation of 3, an inversion of configuration, from S to R, occured and was accompanied by the loss of the hydrogen atom originally present on C-14, as GLC/MS analysis of the products of feeding C. suaveolens with deuterated 10 showed.
- Cardillo, Rosanna,Fronza, Giovanni,Fuganti, Claudio,Grasselli, Piero,Mele, Andrea,et al.
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p. 5237 - 5239
(2007/10/02)
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- Lipase-Catalyzed Preparation of Optically Active γ-Butyrolactones in Organic Solvents
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Lipases in anhydrous organic solvents catalyze the lactonization of esters of γ-hydroxy carboxylic acids with a high degree of stereospecifity.Under these conditions the lipases exhibit both enantioselectivity and prochiral selectivity.We exploited the enzymes' enantioselectivity for synthesis of chiral lactones from racemic γ-hydroxy esters and their prochiral stereospecifity, i.e. the ability to discriminate between enantiotopic groups of a prochiral molecule, for the enantioconvergent lactonization of symmetrical γ-hydroxy diesters.This approach was used to develop a convenient, high yielding, and stereoselective route to several optically active γ-substituted γ-butyrolactones.
- Gutman, Arie L.,Zuobi, Kheir,Bravdo, Tamar
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p. 3546 - 3552
(2007/10/02)
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- Ring Expansion of Cyclopropylmethanols to Cyclobutanes - An Enantioselective Total Synthesis of (R)-(+)-Dodecan-5-olide, and (S)-(+)- and (R)-(-)-5-dihydrofuran-2(3H)-one
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A novel and convenient route to chiral cyclobutanones (8) and (9) by ring expansion of the cyclopropylmethanols (6) and (7) was developed, leading to an enantioselective total synthesis of (R)-(+)-dodecan-5-olide (25), and (S)-(+)- and (R)-(-)-5-dihydrofuran-2(3H)-one (35) and (36) (the pheromone of the Japanese beetle).
- Nemoto, Hideo,Ishibashi, Hiroki,Mori, Masahiko,Fujita, Shigekazu,Fukumoto, Keiichiro
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p. 2835 - 2840
(2007/10/02)
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- An efficient preparation of the optically active γ-hydroxy stannanes using lipase-catalyzed hydrolysis
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A perfect optical resolution of γ-hydroxystannanes was demonstrated by the method of lipase-catalyzed enantioselective hydrolysis of the corresponding racemic acetates using lipase P (Pseudomonas sp.).
- Itoh,Ohta,Sano
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p. 6387 - 6390
(2007/10/02)
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- n-Pentenyl Glycosides as Mediators in the Asymmetric Synthesis of Monosubstituted Chiral Nonracemic Tetrahydrofurans and γ-Lactones
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n-Pentenyl glycosides can be oxidatively hydrolyzed by treatment with N-bromosuccinimide, previous work having been focused on the usefulness of the resulting glycosyl moiety.In this paper, attention is focused on asymmetric induction in the 2-(bromomethyl)furan that is liberated.The enantiomeric excess depends strongly on the orientations at the anomeric centers and at C2, as well as on the protecting group on the C2 oxygen. α-Anomers display higher asymmetric induction, and rationalization of this observation is based on the assumption that the molecule reacts from the favored ground-state orientation, wherein the exo anomeric effect is displayed.The usefulness of this route to optically active furans has been probed by a synthesis of an insect pheromone from the Bledius species.
- Llera, Jose Manuel,Lopez, J. Cristobal,Fraser-Reid, Bert
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p. 2997 - 2998
(2007/10/02)
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- Synthesis of both the enantiomers of 4-dodecanolide, the pheromone of the rove beetle
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A simple and efficient synthesis of the target pheromone in its enantiomeric forms has been formulated using easily accessible (R)-2,3- isopropanedioxyglyceraldehyde (2) as the single starting chiron.
- Chattopadhyay,Mamdapur,Chadha
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p. 3667 - 3672
(2007/10/02)
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- Enantioselective synthesis of 4-substituted γ-lactones
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BINAP-Ru(II) catalyzed hydrogenation of prochiral 4-oxo carboxylic esters and o-acylbenzoates gives either enantiomer of the corresponding γ-lactones in >98% enantiomeric excesses.
- Ohkuma,Kitamura,Noyori
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p. 5509 - 5512
(2007/10/02)
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- Asymmetric Reduction of a Prochiral Carbonyl Group of Aliphatic γ- and δ-Keto Acids by Use of Fermenting Bakers' Yeast
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With use of fermenting bakers' yeast, γ- and δ-keto acids, RCO(CH2)nCO2H (n = 2 and 3; R = C2H5, n-C3H7, n-C4H9, n-C5H17, n-C8H11, n-C11H23 and n-C13H27), were reduced to the corresponding γ- and δ-hydroxy acids which were isolated as γ- and δ-lactones in low to good yields with >98percent ee.The shortest γ- and δ-keto acid (R = CH3) failed to give the hydroxy acids.The reduction of 5-oxohexadecanoic acid (n = 3; R = n-C11H23) was examined under various conditions to improve the chemical yield.The absolute configurations of all of the lactones were determined to be R, even though the Prelog rule predicts the S configurations for the substrates having R = C2H5 and n-C3H7.The role of the carboxy group was discussed in comparison with the results obtained for the δ-keto esters.
- Utaka, Masanori,Watabu, Hisashi,Takeda, Akira
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p. 4363 - 4368
(2007/10/02)
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- KINETIC RESOLUTION OF LACTONES BY ENANTIOSELECTIVE PROTONATION OF THE CORRESPONDING CARBOXYLATE WITH A CHIRAL ACID
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Racemic lactones were optically activated through the hydrolysis with sodium hydroxide followed by the partial neutralisation with (1S)-(+)-10-camphorsulfonic acid in ethanol to afford R- or S-isomer with 99 - 38percent ee.
- Fuji, Kaoru,Node, Manabu,Murata, Makoto,Terada, Shunji,Hashimoto, Keiji
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p. 5381 - 5382
(2007/10/02)
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- Synthesis of the optical antipodes of 4-alkyl-γ-lactones
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Optical antipodes of 4-alkyl-γ-lactones 3 have been prepared by photochemical rearrangement of optically active α,β-epoxy diazomethyl ketones 1 in ethanol to give 4-hydroxy-alkenoates 2, followed by reduction of the alkene bond and subsequent lactonization.The required epoxy diazomethyl ketones 1 were obtained via the following sequence of reactions: alkylation of 2-propyn-1-ol, subsequent reduction to the alkenols 6, Sharpless epoxidation to 2,3-epoxy alcohols 7, oxidation to glycidic esters 8 and finally conversion to diazo ketones 1.The enantiomeric purities range from 84 to 100percent.
- Thijs, Lambertus,Waanders, Peter P.,Stokkingreef, Edwin H. M.,Zwanenburg, Binne
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p. 332 - 337
(2007/10/02)
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- Synthesis of Both the Enantiomers of 4-Dodecanolide, a Defensive Secretion of Rove Beetles
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The enantiomers of 4-dodecanolide, a defensive secretion of rove beetles, were synthesized from (S)- and (R)-2-aminodecanoic acid obtained by the enzymic resolution of the corresponding chloroacetyl derivative.
- Sugai, Takeshi,Mori, Kenji
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p. 2497 - 2500
(2007/10/02)
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- Synthetic Applications of the Enantioselective Reduction by Binaphthol-Modified Lithium Aluminum Hydride Reagents
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The reduction of prochiral carbonyl substrates with the chiral binaphthol-modified lithium aluminum hydride reagents provides an effective means for preparing alcoholic products of high optical purity.The reaction is applicable to a variety of structurally diverse unsaturated carbonyl compounds such as aromatic ketones, acetylenic ketones, olefinic ketones and aldehydes, etc.Either of the antipodes is obtainable in a predictable manner by choosing the handedness of the auxiliary binaphthol ligand.The utility is exemplified by the efficiently stereocontrolled synthesis of prostaglandin intermediates, some insect pheromones, chiral primary terpenic alcohols, optically active styrene oxide, etc.
- Noyori, R.,Tomino, I.,Yamada, M.,Nishizawa, M.
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p. 6717 - 6725
(2007/10/02)
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- Synthesis of Racemates and (+)-Enantiomers of γ-Caprolactone, γ-Dodecanolactone and δ-Hexadecanolactone, Lactonic Sex Pheromones of the Dermestid Beetle, Rove Beetle and Oriental Hornet
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A simple method based on regioselective two-step alkylation of easily-available diethyl 3-oxoglutarate (2) is described for the synthesis of racemates of the lactonic pheromones, 1a, 1b, and 1c.Their (+)-enantiomers were also synthesized by means of microbiological reduction of the intermediary keto acids.
- Naoshima, Yoshinobu,Ozawa, Hiroshi,Kondo, Hirokiyo,Hayashi, Shuichi
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p. 1431 - 1434
(2007/10/02)
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