- Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
-
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
- Oestreich, Martin,Seliger, Jan
-
supporting information
p. 247 - 251
(2020/10/29)
-
- FGFR4 INHIBITOR AND PREPARATION METHOD AND USE THEREOF
-
Provided are a class of compounds as shown in formula (I) as FGFR4 inhibitors, and pharmaceutically acceptable salts thereof, preparation methods therefor and the use thereof in the preparation of drugs for treating FGFR4-related diseases.
- -
-
Paragraph 0265-0268
(2019/10/10)
-
- More than one kind of hydroxy phthalazine compound, preparation method and application thereof (by machine translation)
-
The invention belongs to the field of biomedical technology, in particular to more than one kind of hydroxy phthalazine compound, preparation method and application thereof, the polyhydroxylated phthalazine compounds of the chemical structure of general f
- -
-
Paragraph 0027; 0028; 0030
(2017/09/01)
-
- Iron phthalocyanine as new efficient catalyst for catalytic transfer hydrogenation of simple aldehydes and ketones
-
Catalytic transfer hydrogenation (CTH) of various aldehydes and ketones was studied using iron phthalocyanine catalyst, in order to substitute the typically used rare transition metals (Ir, Rh, Ru) with an easily available and less expensive metal. Iron phthalocyanine was found to be an efficient hydrogenation catalyst and its immobilized version was successfully prepared. The immobilized iron phthalocyanine was also active in the CTH reaction of various carbonyl compounds, and it was easy to handle and possible to recycle.
- Bata, Pter,Notheisz, Ferenc,Kluson, Peter,Zsigmond, gnes
-
-
- Metal-free trifluoromethylation of aromatic and heteroaromatic aldehydes and ketones
-
The ability to convert simple and common substrates into fluoroalkyl derivatives under mild conditions remains an important goal for medicinal and agricultural chemists. One representative example of a desirable transformation involves the conversion of aromatic and heteroaromatic ketones and aldehydes into aryl and heteroaryl β,β,β-trifluoroethylarenes and -heteroarenes. The traditional approach for this net transformation involves stoichiometric metals and/or multistep reaction sequences that consume excessive time, material, and labor resources while providing low yields of products. To complement these traditional strategies, we report a one-pot metal-free decarboxylative procedure for accessing β,β,β- trifluoroethylarenes and -heteroarenes from readily available ketones and aldehydes. This method features several benefits, including ease of operation, readily available reagents, mild reaction conditions, high functional-group compatibility, and scalability.
- Qiao, Yupu,Si, Tuda,Yang, Ming-Hsiu,Altman, Ryan A.
-
p. 7122 - 7131
(2014/08/18)
-
- Ion pairing effects on the regioselectivity of arylic versus benzylic C-O bond reductive cleavage: synthetic applications
-
The regioselectivity of the reductive cleavage of 3,4,5-trimethoxybenzyl methyl ether strongly depends on the alkali metal employed as a reducing agent and solvent effects. Reactions run using Na as a reducing agent led to aromatic C(4)-O bond cleavage, whilst reductions run in the presence of Na/15-crown-5, or using Li as a reducing agent, led to highly regioselective benzylic C-O bond cleavage. This regioselectivity turnaround is discussed in terms of major solvent effects affecting the fragmentation paths of a common reaction intermediate. Synthetic applications of these findings led to the synthesis of biologically active compounds, like 2,5-dialkyl-substituted resorcinols, or 1-(3,4,5-trimethoxyphenyl)-2-arylethanes structurally related to combretastatin.
- Azzena, Ugo,Dettori, Giovanna,Mascia, Ilaria,Pisano, Luisa,Pittalis, Mario
-
p. 11998 - 12006
(2008/03/14)
-
- 2,4-DIAMINOQUINAZOLINES FOR SPINAL MUSCULAR ATROPHY
-
2,4-Diaminoquinazolines of formulae I-IV and VI (I, II, III, IV and VI) are useful for treating spinal muscular atrophy (SMA).
- -
-
Page/Page column 51
(2010/02/15)
-
- Regioselective Reductive Electrophilic Substitution of Derivatives of 3,4,5-Trimethoxybenzaldehyde
-
The behavior of several protected derivatives of 3,4,5-trimethoxybenzaldehyde has been investigated under conditions of electron transfer from alkali metals in aprotic solvents.The 4-methoxy group can be regioselectively removed in good to high yield under such conditions, and an appropriate choice of the protecting group, metal, and solvent allows its substitution with a variety of electrophiles. 3,4,5-Trimethoxybenzaldehyde dimethyl acetal, 1, is the starting material of choice for a new general synthetic approach to several polysubstituted resorcinol dimethyl ethers.Investigation of the mechanism of demethoxymetylation, with the aid of labeling experiments, showed that reductive demethoxylation is strongly influenced by the nature of the aldehyde protective group employed.
- Azzena, Ugo,Melloni, Giovanni,Piroddi, Anna Maria,Azara, Emanuela,Contini, Stefania,Fenude, Emma
-
p. 3101 - 3106
(2007/10/02)
-
- Photochemical Transformation. 48. The Nonconcertedness of Nucleofuge Loss and anti-Aryl Migration in Photochemical Wagner-Meerwein Rearrangements
-
Preparation of the two diastereomeres of 3-(3,5-dimethoxyphenyl)-2-butanol and of their 2-deuterio analogues has been carried out.When the methanesulfonate esters of the diastereomers were solvolyzed by heating at reflux in 50percent aqueous methanol, the resulting alcohols and methyl ethers were formed with complete retention of diastereomeric identity and without measurable hydride migration to give the 2-aryl-2-butyl isomer.Similar treatment of the methanesulfonates of the deuterio analogues gave complete deuterium scrambling, that is, gave equal mixtures of 3-aryl-2-deuterio -2-butyl and 3-aryl-3-deuterio-2-butyl derivatives.These results of ground-state solvolyses are consistent with aryl participation coincident with nucleofuge loss, with bridged phenonium ions as sole intermediates.On the other hand, irradiations of the methanesulfonates with 300-nm light in the same solvent gave photosolvolysis with considerable diastereomeric mixing, although again complete deuterium scrambling was observed here as well.In addition, significant amounts of 2-aryl-2-butanol were formed.The excited-state results require a much more complicated reaction course than the ground-state results, probably involving syn-hydrogen migration to give the tertiary alcohol, along one path, and requiring that the observed aryl migrations, along another path, occur later than, rather than concerted with, nucleofuge loss.
- Cristol, Stanley J.,Ali, Mahfuza B.,Sankar, Iyer V.
-
p. 8207 - 8211
(2007/10/02)
-
- BIOLOGICALLY ACTIVE PHENOLIC METABOLITES OF A VERTICICLADIELLA SPECIES
-
The metabolites produced when a Verticicladiella species (Canadian Forestry Service strain C728), the causative agent of the black stain root disease of many conifers, is grown in liquid culture have been investigated.Orcinol, orcinol monomethyl ether, 1,3,6,8-tetrahydroxyanthraquinone, and the α-L-rhamnopyranosides of orcinol and orcinol methyl ether have been isolated and indentified.Orcinol methyl ether and its rhamnoside both show antibacterial activity and orcinol methyl ether also inhibits the growth of pine germlings.The general antibacterial activity of 5-alkylresorcinols and their monomethyl ethers is reported.-Key Word Index-Verticicladiella sp.; Deuteromycontina; blue-stain fungus; phytotoxin; phenols; methylorcinol rhamnoside; phenol monomethyl ethers; antiseptics.
- Ayer, William A.,Browne, Lois M.,Lovell, Sarah H.
-
p. 2267 - 2272
(2007/10/02)
-
- STEREOCHEMISTRY OF PHOTOSOLVOLYSIS OF A CHIRAL, 18O-LABELED 1-ARYLETHYL ACETATE
-
The stereochemistry of photosolvolysis of (R)-(+)-1-(3,5-dimethoxyphenyl)ethyl acetate-ether-18O in methanol-water and 2,2,2-trifluoroethanol has been determined.An ion pair intermediate was detected in the latter solvent.
- Jaeger, David A.,Angelos, George H.
-
p. 803 - 806
(2007/10/02)
-
