- Diastereoselective synthesis of (2S*)-2-[(R*)-1H-indol-3-yl(phenyl)methyl]-2,3-dihydro-1H-inden-1-one
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Double asymmetric induction in Michael reactions has been studied. Enantioselective alkylation of a cyclic ketone (1-indanone) with α-phenyl-nor-gramine was carried out. The relative configuration of (2S*)-2-[(R*)-1H-indol-3-yl(pheny
- Semenov, Boris B.,Novikov, Kirill A.,Lysenko, Konstantin A.,Kachala, Vadim V.
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- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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supporting information
p. 6084 - 6093
(2019/05/24)
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- Access to 1,2-dihydroisoquinolines through gold-catalyzed formal [4+2] cycloaddition
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A new synthetic route to the privileged 1,2-dihydroisoquinolines is reported. This method, which relies on a gold-catalyzed formal [4+2] cycloaddition between ynamides and imines, provides a new retrosynthetic disconnection of the 1,2-dihydroisoquinoline core by installing the 1,8a C-C and 2,3 C-N bonds in one step. Both aldimines and ketimines can be used as substrates. In addition, one example of dihydrofuropyridine synthesis is also demonstrated. Heterocycles: A new synthetic route to the privileged 1,2-dihydroisoquinolines is reported. This method, which relies on a gold-catalyzed formal [4+2] cycloaddition between ynamides and imines, provides a new retrosynthetic disconnection of the 1,2-dihydroisoquinoline core by installing the 1,8a C-C and 2,3 C-N bonds in one step. Both aldimines and ketimines can be used as substrates. In addition, one example of dihydrofuropyridine synthesis is also demonstrated (see scheme).
- Xin, Zhuo,Kramer, Soren,Overgaard, Jacob,Skrydstrup, Troels
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supporting information
p. 7926 - 7930
(2014/07/07)
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- Initiators based on benzaldoximes: Bimolecular and covalently bound systems
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Typical bimolecular photoinitiators (PIs) for radical polymerization of acrylates show only poor photoreactivity because of the undesired effect of back electron transfer. To overcome this limitation, PIs consisting of a benzaldoxime ester and various sensitizers based on aromatic ketones were introduced. The core of the photoinduced reactivity was established by laser flash photolysis, photo-CIDNP, and EPR experiments at short time scales. According to these results, the primarily formed iminyl radicals are not particularly active. The polymerization is predominantly initiated by C-centered radicals. Photo-DSC experiments show reactivities comparable to that of classical monomolecular type I PIs like Darocur 1173.
- Griesser, Markus,Rosspeintner, Arnulf,Dworak, Claudia,Hoefer, Michael,Grabner, Gottfried,Liska, Robert,Gescheidt, Georg
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p. 8648 - 8657
(2013/01/15)
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- o-Iodoxybenzoic Acid (IBX) as a Viable Reagent in the Manipulation of Nitrogen- and Sulfur-Containing Substrates: Scope, Generality, and Mechanism of IBX-Mediated Amine Oxidations and Dithiane Deprotections
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o-Iodoxybenzoic acid (IBX), a highly versatile hypervalent iodine(V) reagent, was found to efficiently mediate the dehydrogenation of amines in addition to facilitating the oxidative cleavage of dithioacetals and dithioketals. Through the development of relevant IBX-based protocols, a plethora of useful synthetic intermediates, including imines, oximes, ketones, and aromatic N-heterocycles, were found to be readily accessible under notably mild conditions. Further investigation of these transformations led to the elucidation of valuable mechanistic details, resulting in the conclusion that they proceed via ionic rather than single electron transfer (SET) pathways.
- Nicolaou,Mathison, Casey J. N.,Montagnon, Tamsyn
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p. 5192 - 5201
(2007/10/03)
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- New reactions of IBX: Oxidation of nitrogen- and sulfur-containing substrates to afford useful synthetic intermediates
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New reactions for the synthetic toolbox: 2-lodoxybenzoic acid (IBX) was employed to access a diverse array of useful synthetic intermediates. Among other transformations, the developed chemistry converts amines into imines, dithianes into carbonyl groups, N-heterocycles into N-heteroaromatic compounds, and hydroxylamines into oximes in high yields.
- Nicolaou,Mathison, Casey J. N.,Montagnon, Tamsyn
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p. 4077 - 4082
(2007/10/03)
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