88981-35-5Relevant articles and documents
Bispalladacycle Catalyzed Nucleophilic Enantioselective Allylation of Aldehydes by Allylstannanes
Frey, Wolfgang,Heberle, Martin,Legendre, Sarah,Peters, René,Wannenmacher, Nick,Weber, Manuel
, (2022/03/08)
Enantiopure homoallylic secondary alcohols are very important synthetic building due to the versatility of the hydroxyl and olefin moieties. A key strategy to prepare them is by nucleophilic allylation of aldehydes. A large number of catalyst concepts emerged that allow for high enantioselectivity. Still, in many target-oriented syntheses of complex structures stoichiometric methods are preferred over catalytic ones. The need for high catalyst loadings and long reaction times, plus unsatisfying reproducibility and substrate scopes are reasons for that. In the present study we report the first palladium catalysts capable of controlling asymmetric nucleophilic allylations of aldehydes with allyltributyltin. TONs up to 620 were achieved, which is significantly higher than for any other reported catalyst. The method is also tolerating electronically and sterically unfavorable substrates. We show that a transmetallation occurs, favoring an η1-allyl coordination mode with the bispalladacycles. In contrast, for the corresponding monopalladacycle an unproductive η3 coordination is dominant.
Stereoselective total synthesis of (?)-galantinic acid and 1-deoxy-5-hydroxysphingolipids via prins cyclization
Rahman, Md. Ataur,Haque, Ashanul,Yadav, Jhillu Singh
supporting information, (2020/07/03)
The stereoselective total synthesis of (?)-galantinic acid 1 and 1-deoxy-5-hydroxysphingolipids 4 is described via Prins cyclization protocol followed by reductive ring opening sequence of substituted pyrenol derivative 6. The target molecules were synthesized using a common synthetic intermediate epoxide 5. Besides, we also proposed synthetic pathways to achieve other structural analogues using common intermediates.
Development of a Practical, Biocatalytic Synthesis of tert-Butyl (R)-3-Hydroxyl-5-hexenoate: A Key Intermediate to the Statin Side Chain
Chen, Fener,Hu, Chen,Huang, Zedu,Liu, Minjie,Yue, Xiaoping
supporting information, p. 1700 - 1706 (2020/10/26)
The HMG-CoA reductase inhibitors, statins, are one of the most effective and bestselling cholesterol-lowering drugs. The use of statins has greatly extended people's lives and improved the quality of their life. Development of a more efficient, stereoselective, and sustainable synthesis of statins is continuingly of utmost importance. In the present study, through screening of ketoreductases (KREDs) and reaction optimization, we have successfully performed a highly stereoselective reduction of ketoester 1a catalyzed by KRED-06 at a pilot-plant scale without the addition of exogenous NADP+, generating 3.21 kg of enantiomerically pure tert-butyl (R)-3-hydroxyl-5-hexenoate ((R)-2a) (96.2% yield, >99.9% enantiomeric excess (ee)). This newly developed biocatalytic process alleviates the cryogenic conditions (-40 °C) employed in our first-generation synthesis of (R)-2a using NaBH4 and (l)-tartaric acid. Coupled with our previously established synthesis of bromocarbonate 3a via a one-pot diastereoselective carboxylation/bromocyclization of (R)-2a, we have developed an innovative, practical synthesis route to statin side chain, possessing great potential to be implemented into industrial production of statins.
Bi(cyclopentyl)diol-Derived Boronates in Highly Enantioselective Chiral Phosphoric Acid-Catalyzed Allylation, Propargylation, and Crotylation of Aldehydes
Yuan, Jinping,Jain, Pankaj,Antilla, Jon C.
, p. 12988 - 13003 (2020/11/23)
In this study, we disclose the catalytic addition of bi(cyclopentyl)diol-derived boronates to aldehydes promoted by chiral phosphoric acids, allowing for the formation of enantioenriched homoallylic, propargylic, and crotylic alcohols (up to >99% enantiom
Synthesis, conformation, and biological activities of a des-a-ring analog of 18-deoxy-aplog-1, a simplified analog of debromoaplysiatoxin
Ashida, Yoshiki,Yanagita, Ryo C.,Kawanami, Yasuhiro,Okamura, Mutsumi,Dan, Shingo,Irie, Kazuhiro
, p. 942 - 957 (2019/08/01)
10-Me-Aplog-1 as a simplified analog of tumor-promoting debromoaplysiatoxin and a potent activator of protein kinase C (PKC) is a promising chemotherapeutic agent. In this study, we synthesized a des-A-ring analog (4) of 18-deoxy-aplog-1 as a syntheticall
AMINOTHIAZINES AND THEIR USE AS BACE1 INHIBITORS
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Page/Page column 13, (2018/03/06)
The present invention provides a compound of Formula I: or a pharmaceutically acceptable salt thereof, and the use of compounds of Formula I for treatment of neurodegenerative diseases and disorders, such as Alzheimer's disease.
Remarkable Influence of Cobalt Catalysis on Epoxide Ring-Opening with Sulfoxonium Ylides
Jamieson, Megan L.,Brant, Nicola Z.,Brimble, Margaret A.,Furkert, Daniel P.
, p. 3952 - 3956 (2017/08/29)
Cobalt demonstrates a remarkable ability to catalytically divert the course of epoxide to oxetane ring expansion via reaction with a sulfoxonium ylide. An expanded survey of transition-metal catalysts has confirmed that cobalt salts uniquely instead deliv
C5-C6-OXACYCLIC FUSED IMINOPYRIMIDINONE COMPOUNDS AS BACE INHIBITORS, COMPOSITIONS, AND THEIR USE
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Page/Page column 46, (2016/06/14)
In its many embodiments, the present invention provides certain C5-C6-oxacyclic fused iminopyrimidinone compounds, including compounds Formula (I): or a tautomer thereof, and pharmaceutically acceptable salts of said compounds and said tautomers, wherein RN, R1, RA, ring A, m, n, -L1-, ring B, RB, and p are as defined herein. The novel compounds of the invention are useful as BACE inhibitors and/or for the treatment and prevention of various pathologies related thereto. Pharmaceutical compositions comprising one or more such compounds (alone and in combination with one or more other active agents), and methods for their preparation and use, including for the possible treatment of Alzheimer's disease, are also disclosed.
Divergent reactivity via cobalt catalysis: An epoxide olefination
Jamieson, Megan L.,Hume, Paul A.,Furkert, Daniel P.,Brimble, Margaret A.
, p. 468 - 471 (2016/02/18)
Cobalt salts exert an unexpected and profound influence on the reactivity of epoxides with dimethylsulfoxonium methylide. In the presence of a cobalt catalyst, conditions for epoxide to an oxetane ring expansion instead deliver homoallylic alcohol products, corresponding to a two-carbon epoxide homologation/ring-opening tandem process. The observed reactivity change appears to be specifically due to cobalt salts and is broadly applicable to a variety of epoxides, retaining the initial stereochemistry. This transformation also provides operationally simple access to enantiopure homoallylic alcohols from chiral epoxides without use of organometallic reagents. Tandem epoxidation-homologation of aldehydes in a single step is also demonstrated.
Stereoselective Synthesis of the C(1)?–?C(28) Fragment of Amphidinol 3
Yadav, Jhillu S.,Gopalarao, Yerragorla,Chandrakanth, Dandekar,Reddy, Basi V. Subba
, p. 436 - 446 (2016/07/06)
A stereoselective synthesis of the polyol side chain (C(1)?–?C(28)) of amphidinol 3 has been accomplished following Sharpless epoxidation, Crimmins aldol reaction, Jacobsen kinetic resolution, Sharpless asymmetric dihydroxylation, and our own reaction for
