65376-02-5Relevant academic research and scientific papers
Asymmetric desymmetrization of meso-tetrahydrofuran derivatives by highly enantiotopic selective C-H oxidation
Miyafuji, Akio,Katsuki, Tsutomu
, p. 10339 - 10348 (1998)
Asymmetric desymmetrization of meso-tetrahydrofuran derivatives was successfully achieved by Mn-salen catalyzed enantiotopic selective C-H oxidation, giving optically active lactols (up to 90% ee) which serve as useful chiral building blocks for organic synthesis.
(Salen)ruthenium-catalyzed desymmetrization of meso-diols: Catalytic aerobic asymmetric oxidation under photo-irradiation
Shimizu, Hideki,Nakata, Kenya,Katsuki, Tsutomu
, p. 1080 - 1081 (2002)
Catalytic aerobic oxidation of meso-diols using (nitrosyl)-Ru(salen) 7 as the catalyst under photo-irradiation proceeded with moderate enantioselectivity (up to 67% ee) to give the corresponding lactols.
Catalytic enantioselective desymmetrization of meso cyclic anhydrides via iridium-catalyzed hydrogenation
Liu, Tang-Lin,Li, Wei,Geng, Huiling,Wang, Chun-Jiang,Zhang, Xumu
, p. 1740 - 1743 (2013)
A novel method to desymmetrize meso-anhydrides into lactones via asymmetric hydrogenation catalyzed by the Ir-C3*-TunePhos complex has been developed. Various chiral lactones were synthesized with full conversion and excellent enantioselectivit
Simple Preparation of Rhodococcus erythropolis DSM 44534 as Biocatalyst to Oxidize Diols into the Optically Active Lactones
Martinez-Rojas, Enriqueta,Olejniczak, Teresa,Neumann, Konrad,Garbe, Leif-Alexander,Boraty?ski, Filip
, p. 623 - 627 (2016/10/11)
In the current study, we present a green toolbox to produce ecological compounds like lactone moiety. Rhodococcus erythropolis DSM 44534 cells have been used to oxidize both decane-1,4-diol (2a) and decane-1,5-diol (3a) into the corresponding γ- (2b) and δ-decalactones (3b) with yield of 80% and enantiomeric excess (ee)?=?75% and ee?=?90%, respectively. Among oxidation of meso diols, (?)-(1S,5R)-cis-3-oxabicyclo[4.3.0]non-7-en-2-one (5a) with 56% yield and ee?=?76% as well as (?)-(2R,3S)-cis-endo-3-oxabicyclo[2.2.1]dec-7-en-2-one (6a) with 100% yield and ee?=?90% were formed. It is worth mentioning that R. erythropolis DSM 44534 grew in a mineral medium containing ethanol as the sole source of energy and carbon Chirality 28:623–627, 2016.
Polymerization of epoxide with hydroxylamides as thermally latent initiators
Wang, Yanmei,Kimura, Mika,Sudo, Atsushi,Endo, Takeshi
, p. 2611 - 2617 (2016/07/14)
A new class of thermally latent initiators for the ring-opening polymerization of epoxides has been developed. The latent initiators developed herein were the hydroxylamides 1a, 1b, and 1c, which were synthesized from phthalide, 3-isochromanone, and cis-cyclohexahydrophthalide, respectively, by their ring-opening reactions with pyrrolidine. These hydroxylamides were designed so that their hydroxyl groups could attack the amide moiety intramolecularly upon heating, leading to ring closure and formation of the corresponding lactones while releasing pyrrolidine, the initiator for the anionic ring-opening polymerization of an epoxide. The temperatures at which this thermal dissociation occurred were strongly dependent on the hydroxylamide molecular structure. When using the hydroxylamides as thermally latent initiators, the polymerizations of bisphenol-A diglycidyl ether were investigated at various temperatures. This investigation clarified that the threshold temperature, that is, the temperature at which polymerization was initiated, increased in the order of 1a, 1b, and then 1c.
Type II flavin-containing monooxygenases: A new class of biocatalysts that harbors baeyer-villiger monooxygenases with a relaxed coenzyme specificity
Riebel, Anette,Fink, Michael J.,Mihovilovic, Marko D.,Fraaije, Marco W.
, p. 1112 - 1117 (2014/05/06)
Within a newly identified set of flavin-containing monooxygenases (FMOs) from Rhodococcus jostii RHA1, we have identified three monooxygenases (FMO-E, FMO-F, and FMO-G) that are effective in catalyzing Baeyer-Villiger oxidations. These type II FMOs display relaxed coenzyme specificity by accepting both NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) and NADH (reduced form of nicotinamide adenine dinucleotide), as a coenzyme, which is a novel and attractive feature among biocatalysts capable of conducting Baeyer-Villiger oxidations. We purified FMO-E and determined that the Michaelis constants for both coenzymes were in the micromolar range, whereas the activity was highest for NADH. By using the stopped-flow technique, formation of a peroxyflavin-enzyme intermediate was observed, which indicated that type II FMOs follow a catalytic mechanism similar to that of other class B flavoprotein monooxygenases. A set of cyclobutanones and cyclohexanones were used to probe the regio- and enantioselectivity of all three recombinant monooxygenases. The biocatalysts readily accepted small cyclic ketones, which enabled the conversion of previously poorly accepted substrates by other monooxygenases (especially norcamphor), and exhibited excellent and unique regio- and enantioselectivities. Sequence analysis revealed that type II FMOs that act as Baeyer-Villiger monooxygenases contain a unique N-terminal domain. Sequence conservation in this protein domain can be used to identify new NADH-dependent Baeyer-Villiger monooxygenases, which would facilitate future biocatalyst discovery efforts. New kid on the block: Members of a newly recognized group of sequence-related flavin-containing monooxygenases can perform Baeyer-Villiger oxidations. Their coenzyme indifference and unique specificity make them attractive biocatalysts.
Aerobic oxidative desymmetrization of meso-diols with bifunctional amidoiridium catalysts bearing chiral N-sulfonyldiamine ligands
Moritani, Junki,Hasegawa, Yasuharu,Kayaki, Yoshihito,Ikariya, Takao
supporting information, p. 1188 - 1191 (2014/02/14)
Asymmetric aerobic oxidation of a range of meso- and prochiral diols with chiral bifunctional Ir catalysts is described. A high level of chiral discrimination ability of Cpa? -Ir complexes derived from (S,S)-1,2-diphenylethylenediamine was successfully demonstrated by desymmetrization of secondary benzylic diols such as cis-indan-1,3-diol and cis-1,4-diphenylbutane-1,4-diol, providing the corresponding (R)-hydroxyl ketones with excellent chemo- and enantioselectivities. Enantiotopic group discrimination in oxidation of symmetrical primary 1,4- and 1,5-diols gave rise to chiral lactones with moderate ees under similar aerobic conditions.
Microbial alcohol dehydrogenase screening for enantiopure lactone synthesis: Down-stream process from microtiter plate to bench bioreactor
Boratyński,Pannek,Walczak,Janik-Polanowicz,Huszcza,Szczepańska,Martinez-Rojas,Olejniczak
, p. 1637 - 1646 (2015/02/05)
One-pot conversion with whole cells of bacteria was performed for biooxidation of meso monocyclic (3a-b) and bicyclic diols (3c-e) into corresponding chiral lactones of bicyclo[4.3.0]nonane structure (2a-b) as well as exo- and endo-bridged lactones with the structure of [2.2.1] (3c-d) and [2.2.2] (3e). Micrococcus sp. DSM 30771 was selected as biocatalyst with significant alcohol dehydrogenase activity. Among tested strains, microbial oxidation of meso diols 3a-e catalyzed by Micrococcus sp. afforded enantiomerically pure ((+)-(2S,3R)-2c (ee = 99%), (+)-(2S,3R)-2e (ee = 99%)) or enriched ((+)-(1S,5R)-2a (ee = 90%), (-)-(1S,5R)-2b (ee = 86%), (+)-(2S,3R)-2d (ee = 80%)) lactone moieties. Comparative study with respect to microbial cultivation as well as biooxidation was undertaken to verify agreement of secondary metabolite biosynthesis in different scales: from MTP (4 mL), across shake flask (100 mL) till bioreactor (4 L). The results from biotransformations showed quite similar dependence in oxidation of all substrates 3a-e in MTP and flasks as well, thereby confirmed the validity and reasonable approach of using MTP for preliminary studies.
One-Pot Bi(OTf)catalyzed oxidative deprotection of tert -butyldimethyl silyl ethers with TEMPO and co-oxidants
Barnych, Bogdan,Vatèle, Jean-Michel
experimental part, p. 2048 - 2052 (2011/10/19)
A sequential one-pot synthesis for the oxidation of primary and secondary tert-butyldimethylsilyl (TBDMS) ethers, using catalytic amounts of metal triflates and TEMPO in combination with PhIO or PhI(OAc)in THF or acetonitrile, is described. Acid-sensitive protecting groups such as methylidene, isopropylidene, acetals, and Boc are unaffected under the reaction conditions. Another feature of this procedure is its high selectivity for TBDMS ethers over tert-butyldiphenylsilyl ethers and of aliphatic TBDMS groups over phenolic TBDMS groups. Georg Thieme Verlag Stuttgart - New York.
Catalytic Preparation of Cyclic Carboxylic Esters
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Page/Page column 12, (2009/12/02)
Preparation of cyclic esters by hydrogenation of a carbonyl group in at least one anhydride radical —C(O)—O—C(O)— of a cyclic dicarboxylic or polycarboxylic anhydride by means of hydrogen in the presence of a homogeneous noble metal catalyst, characterized in that the hydrogenation is carried out in a homogeneous reaction mixture using an iridium catalyst. The cyclic esters are obtained in good chemical and optical yields when prochiral anhydrides are used together with chiral iridium catalysts.
