نتایج جستجو برای: imines
تعداد نتایج: 2655 فیلتر نتایج به سال:
In enzymology, as in organic chemistry, many transformations revolve around the chemistry of the carbonyl group. A carbonyl group is electrophilic how can it be made more so? Hydrogens next to a carbonyl group have a reduced pK, how can this reactivity be promoted? Nature has found several ways to address these mechanistic challenges, the most important of which is the use of imines. Studies on...
Ni(0)-catalyzed dehydrogenation of benzylic-type imines was performed to yield asymmetrical tetra-substituted imidazoles and 2-imidazolines. This was achieved with a single operational step while maintaining good selectivity and atom economy. The catalytic system shows low to moderate tolerance for fluoro-, trifluoromethyl-, methyl-, and methoxy-substituted benzylic-type imines. In addition, th...
This review is oriented toward the asymmetric transfer hydrogenation (ATH) of imines regarding mostly fundamental, yet important topics from the practical point of view. Development of analytical methods for the monitoring of ATH (i.e., kinetics and stereoselectivity) belongs to those topics, as well as studies on the influence of reaction conditions and structural variations on the reaction pe...
The default explanation for good to high diastereomeric excess when reducing N-chiral imines possessing only mediocre cis/trans-imine ratios (>15% cis-imine) has invariably been in situ cis-to-trans isomerization before reduction; but until now no study unequivocally supported this conclusion. The present study co-examines an alternative hypothesis, namely that some classes of cis-imines may ho...
An iron-catalyzed transfer hydrogenation of N-aryl and N-alkyl imines using isopropanol as the hydrogen donor is reported for the first time. A combination of two iron complexes serving different roles is the key for the success of this catalytic system. As a result, an environmentally friendly and precious metal-free transfer hydrogenation of imines has been developed. The use of a suitable co...
A selective atmospheric hydrogenation of unsaturated imines over heterogeneous iridium catalyst is described, in addition the selectivity elucidated by DFT-calculations.
Photochemical reactions of imines, hydrazones, oximes and related compounds provides an efficient access to radical intermediates in the synthesis heterocycles.
Phosphine-catalyzed [3 + 2] cycloaddition of Morita-Baylis-Hillman carbonates with sulfamate-derived cyclic imines has been developed, affording sulfamate-fused dihydropyrroles in moderate to good yields.
Highly substituted pyrrolidines are prepared by formal cycloaddition of imines to a metal-stabilised 'Nicholas' dipole derived from an alkyne-cyclopropane dicobalt complex.
Herein we report directed iridium-catalyzed C3−H silylation of furfuryl imines, which grants access to versatile synthetic platforms. This transformation was developed on derivatives, using imines as directing groups, and trialkylsilanes or bis(trimethylsilyl)methylsilane silylating agents, in the presence a hydride scavenger. Subsequently, fluoride-mediated activation strategies were applied C...
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