Assuntos
Anestesiologia/normas , Ansiedade/psicologia , Certificação/normas , Conselhos de Especialidade Profissional/normas , Anestesia por Inalação/normas , Insuficiência da Valva Aórtica/fisiopatologia , Insuficiência da Valva Aórtica/terapia , Humanos , Manejo da Dor , Medição da Dor , Salicilatos/efeitos adversos , Sociedades Médicas , Neuralgia do Trigêmeo/terapia , Ferimentos e Lesões/terapiaRESUMO
Dynamic kinetic asymmetric transformation (DYKAT) of 1,5-diols via combined lipase and ruthenium catalysis provides enantiomerically pure diacetates in high diastereoselectivity, which can serve as intermediates in natural product synthesis. This is demonstrated by the synthesis of (+)-Solenopsin A.
Assuntos
Álcoois/química , Alcaloides/síntese química , Lipase/metabolismo , Rutênio/química , Alcaloides/química , Catálise , Cinética , Lipase/química , Estrutura Molecular , EstereoisomerismoRESUMO
Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,5-diols has been performed in the presence of Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase II (PS-C II), and ruthenium catalyst 4. The resulting optically pure 1,5-diacetates are useful synthetic intermediates, which was demonstrated by the syntheses of both an enantiopure 2,6-disubstituted piperidine and an enantiopure 3,5-disubstituted morpholine.
Assuntos
Álcoois/química , Compostos Heterocíclicos/síntese química , Burkholderia cepacia/enzimologia , Catálise , Proteínas Fúngicas , Compostos Heterocíclicos/química , Cinética , Lipase/química , Estrutura Molecular , Rutênio/química , EstereoisomerismoRESUMO
The Sonogashira coupling of electron-deficient (hetero)aryl halides 1 and (hetero)aryl or alkenyl 1-propargyl alcohols 2 does not terminate at the stage of the expected internal propargyl alcohols, but rather gives rise to the formation of alpha,beta-unsaturated ketones 3 with a variety of acceptor substituents. This new domino reaction, a coupling-isomerization reaction (CIR), can be rationalized as a sequence of rapid Pd/Cu-catalyzed alkynylation followed by a slow amine-base-catalyzed propargyl alcohol-enone isomerization. Performing the CIR in deuterated protic solvents or with a selectively deuterated propargyl alcohol revealed that the base-catalyzed isomerization step proceeds through a formal 1,3-H shift with minimal H/D exchange with the surrounding solvent. Additionally, 19F NMR kinetic measurements on the isomerization step with the fluorinated propargyl alcohol 4 r support the mechanistic rationale.
Assuntos
Chalconas/síntese química , Alcenos/química , Alcinos/química , Aminas/química , Catálise , Cobre/química , Hidrocarbonetos Halogenados/química , Isomerismo , Cinética , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Paládio/química , Propanóis/químicaRESUMO
The coupling-isomerization-reaction (CIR) of an electron-deficient halide 1 with 1-(p-bromo phenyl) propyne-1-ol (2) leads to an in-situ activation of the carbon-bromine bond towards oxidative addition and has been elaborated to a consecutive CIR-coupling sequence where subsequent palladium catalyzed coupling reactions such as Sonogashira, CIR, Heck, or Suzuki reactions allow a rapid construction of more complex frameworks in a one-pot reaction and in moderate to good yields.
