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Now showing items 3521-3530 of 4794
Enantioselective Synthesis of Tropanes: Brønsted Acid Catalyzed Pseudotransannular Desymmetrization
(Wiley-VCH, 2020-02-10)
The enantioselective synthesis of tropanols has been accomplished through chiral phosphoric acid catalyzed pseudotransannular ring opening of 1-aminocyclohept-4-ene-derived epoxides. The reaction proceeds together with the ...
Catalytic enantioselective domino Michael/transannular aldol reaction under bifunctional catalysis
(Royal Society of Chemistry, 2020-09-28)
The enantioselective Michael reaction catalyzed by a bifunctional tertiary amine/squaramide has been used to trigger a Michael/transannular aldol cascade process that leads to densely substituted bicyclo[5.4.0]undecanes ...
Catalytic Enantioselective Cloke–Wilson Rearrangement
(Wiley-VCH, 2018-05-09)
Racemic cyclopropyl ketones undergo enantioselective rearrangement to deliver the corresponding dihydrofurans in the presence of a chiral phosphoric acid as the catalyst. The reaction involves activation of the donor-acceptor ...
γ-Substituted Allenic Amides in the Phosphine-Catalyzed Enantioselective Higher Order Cycloaddition with Azaheptafulvenes
(American Chemical Society, 2020-05-28)
Racemic γ-substituted allenes undergo enantioselective higher order [8 + 2]-cycloaddition with azaheptafulvenes using a chiral amino acid derived amidophosphine as catalyst, providing the corresponding azaazulenoid ...
Catalytic Enantioselective Transannular Morita–Baylis–Hillman Reaction
(American Chemical Society, 2019)
Catalytic and enantioselective approaches to transannular reactions are very limited and mostly are based on chiral Lewis acid catalyzed pericyclic reactions. In this report, we present an efficient and straightforward ...
Cp*Co(III)-Catalyzed C−H Hydroarylation of Alkynes and Alkenes and Beyond: A Versatile Synthetic Tool
(ACS, 2020-09-15)
The use of earth-abundant first-row transition
metals, such as cobalt, in C−H activation reactions for the
construction and functionalization of a wide variety of structures
has become a central topic in synthetic ...
Ion-pairing catalysis in the enantioselective addition of hydrazones to N-acyldihydropyrrole derivatives
(Royal Society of Chemistry, 2018-07-16)
We have demonstrated that dihydropyrrole-based enamide derivatives can act as efficient precursors of chiral quaternary N-acyliminium salts under Brønsted acid catalysis that undergo reactions with hydrazones, the latter ...
Reflexiones en torno al «juego de velos» del "Fedro" y una posible alusión al "Hipólito velado"
(Ediciones Complutense, 2017-04)
El presente texto nace como anexo a una investigación previa sobre el Fedro de Platón. En aquella ocasión, al elaborar un nuevo comentario del diálogo en su totalidad, tuvimos que refl exionar acerca de los posibles sentidos ...
Self-heterodyne detection for SNR improvement and distributed phase-shift measurements in BOTDA
(IEEE, 2012-09-26)
In this paper we present a Brillouin optical time domain analysis (BOTDA) sensor that takes advantage of the enhanced characteristics obtained employing self heterodyne optical detection combined with synchronous demodulation. ...
Erlazio-atzizkia eta hitz-ordenaren aldaketa
(Gobierno de Navarra, 2019-06-14)
Lan honetan -ko erlazio-atzizkia duten sintagmen kokapena (izenaren aurrekoa eta izenaren ostekoa) aztertzen da ikuspuntu diakronikotik. Atzizkiaren funtzioa izenen modifikatzaileak sortzea da, adberbioetatik, leku kasua, ...