74034-73-4Relevant academic research and scientific papers
Desymmetrization of acid anhydride with asymmetric esterification catalyzed by chiral phosphoric acid
Yamada, Ken-ichi,Oonishi, Akinori,Kuroda, Yusuke,Harada, Shingo,Kiyama, Hiroki,Yamaoka, Yousuke,Takasu, Kiyosei
supporting information, p. 4098 - 4100 (2016/08/18)
Asymmetric desymmetrization of σ-symmetric acid anhydrides was achieved with chiral phosphoric acid as a Br?nsted acid catalyst. The key of success was finding of benzhydrol and 2,2-diphenylethanol as the nucleophiles of choice. The corresponding half esters were obtained in good yields with high selectivity.
A Diels-Alder macrocyclization enables an efficient asymmetric synthesis of the antibacterial natural product abyssomicin C
Zapf, Christoph W.,Harrison, Bryce A.,Drahl, Carmen,Sorensen, Erik J.
, p. 6533 - 6537 (2007/10/03)
An efficient and highly diastereoselective intramolecular Diels-Alder reaction is the basis of a concise asymmetric synthesis of the potent antibacterial natural product abyssomicin C (see formula). The complexity of the target structure was reduced to three fragments and required two carbonyl addition reactions to achieve key bond formations. (Figure Presented).
Highly enantioselective catalytic thiolysis of prochiral cyclic dicarboxylic anhydrides utilizing a bifunctional chiral sulfonamide
Honjo, Takashi,Sano, Shigeki,Shiro, Motoo,Nagao, Yoshimitsu
, p. 5838 - 5841 (2007/10/03)
(Chemical Equation Presented) A catalytic desymmetrization is achieved for various prochiral dicarboxylic anhydrides with yields of 87-100% and ee values of 83-98% through the title reaction (see scheme; Bn = benzyl). The bifunctional effect of the chiral sulfonamide catalyst was clarified on the basis of unsuccessful asymmetric induction by using the related chiral sulfonamides.
Synthetic routes to the stereoisomers of 2,4-dimethylpentane-1,5-diol derivatives
Mas, Gemma,González, Llu?sa,Vilarrasa, Jaume
, p. 8805 - 8809 (2007/10/03)
Five different routes to every stereoisomer of non-symmetric derivatives of 2,4-dimethylpentanedioic acid and/or of O-monoprotected 2,4-dimethylpentane- 1,5-diols, which are common building blocks for the total synthesis of many polypropionates, have been investigated. Alkylation of the lithium enolate of N-propanoylpseudoephedrine turned out to be the most appropriate method, in connection with the synthesis of fragment C1-C5 of amphidinolide K.
Synthesis of (-)-Probetaenone I: Structural Confirmation of Biosynthetic Precursor of Betaenone B
Miki, Shokyo,Sato, Yoshihiro,Tabuchi, Hiroyasu,Oikawa, Hideaki,Ichihara, Akitami,Sakamura, Sadao
, p. 1228 - 1229 (2007/10/02)
(-)-Probetaenone I (1) has been synthesized by an intramolecular Diels-Alder reaction and, thereby, its structure has been clearly confirmed; in the biosynthesis of betaenone B (2) the stereochemistry of the C-8 hydroxylation of (1) was proved to involve retention of configuration.
Enantiotopic-group Differentation. Catalytic Asymmetric Ring-opening of Prochiral Cyclic Acid Anhydrides with Methanol, using Cinchona Alkaloids
Hiratake, Jun,Inagaki, Minoru,Yamamoto, Yukio,Oda, Jun'ichi
, p. 1053 - 1058 (2007/10/02)
Asymmetric ring-opening of prochiral acid anhydrides (1) with methanol has been achieved by a catalytic quantity of cinchona alkaloids (2).The product, the optically active half-ester (3), has been subjected to functional-group-selective reduction to give the optically active lactones (5).The reaction rate of the ring-opening and the extent of selectivity are dependent on the nature of the reaction medium, the polarity of solvent, and substrate concentration.By selecting the reaction conditions, an enantiometric excess of up to 70percent has been obtained.The kinetic isotope effect and other mechanistic investigations suggest that the reaction proceeds via general-base catalysis by the quinuclidine moiety of the base (2), and that the relative configuration of the C-9 hydroxy group with respect to the C-8 quinuclidine amino function determines the selectivity of the reaction.
Macrocyclic Pyrrolizidine Alkakoid Analogues. Synthesis and Stereochemistry of (12R,14S)-and (12S,14R)-12,14-Dimethyl-1,2-didehydrocrotalanine. X-Ray Molecular Structure of the (12S,14R)-Isomer
Brown, Kenneth,Burton, Michael,Robins, David J.,Sim, George A.
, p. 1261 - 1266 (2007/10/02)
Treatment of (+)-retronecine (1) with meso-2,4-dimethylglutaric anhydride followed by lactonisation via the pyridine-2-thiol esters yielded (12R,14S)-(3) and (12S,14R)-dimethyl-1,2-didehydrocrotalanine (4).These pyrrolizidine alkaloid analogues were separated by column chromatography.The absolute configuration of the acid portion of each analogue was established by a seguence of two chemoselective reactions to afford optically active tetrahydro-3,5-dimethyl-2H-pyran-2-one.An X-ray crystal structure analysis confirmed the structure and stereochemistry of the (12S,14R)-isomer (4).The ester carbonyl groups of compound (4) are synparallel and directed below the plane of the macrocyclic ring.
SYNTHESIS OF BOTH THE ENANTIOMERS OF LARDOLURE, THE AGGREGATION PHEROMONE OF THE ACARID MITE, LARDOGLYPHUS KONOI
Mori, Kenji,Kuwahara, Shigefumi
, p. 5539 - 5544 (2007/10/02)
Both the enantiomers of lardolure were synthesized in 100 percent optical purity and 99.6 percent diastereomeric purity by use of Frater's diastereoselective alkylation as the key-step.Since (1R,3R,5R,7R)-enantiomer showed the same ORD sign and bioactivity as those shown by the natural pheromone, the structure of lardolure was established unambiguously as (1R,3R,5R,7R)-1,3,5,7-tetramethyldecyl formate.
An Asymmetric Synthesis of Lactones from Cyclic Acid Anhydrides with Chiral Binaphthyldiamines
Kawakami, Yukio,Hiratake, Jun,Yamamoto, Yukio,Oda, Jun'ichi
, p. 693 - 698 (2007/10/02)
Asymmetric ring opening of the cyclic acid anhydrides cis-2,3-6 with the axially dissymmetric binaphthyldiamines (S)-1a-d and subsequent esterification gave diastereomeric mixtures of the amide-esters 7a-h.Successive reduction of the ester group and ring closure by hydrolysis afforded (-)-cis-2,4-dimethyl-δ-valerolactone (8, 92percent e.e.), (-)-mevalonolactone (9, 58percent e.e.)(+)-3-isopropyl-δ-valerolactone (10, 42percent e.e.), and (+)-2,3-methylene-γ-butyrolactone (11, 46percent e.e).Through kinetic resolution of the racemic anhydride trans-2, (-)-trans-2,4-dimethyl-δ-valerolactone (12) was yielded in a 74percent e.e., whose absolute configuration was established to be 2R,4R.
Catalytic Asymmetric Induction from Prochiral Cyclic Acid Anhydrides using Cinchona Alkaloids
Hiratake, Jun,Yamamoto, Yukio,Oda, Jun'ichi
, p. 1717 - 1719 (2007/10/02)
Asymmetric ring-opening of prochiral cyclic acid anhydrides (1) with methanol was effected by a catalytic amount of cinchona alkaloids (2) with an enantiomeric excess of up to 70percent and the product was converted into optically active lactones.
