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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(24):7103-7106
β‐Ketonitriles bearing a quaternary carbon at the 2‐position were prepared through Rh‐catalyzed addition of aryl boronic acids to 2,2‐disubstituted malononitriles. In contrast to the previously described transnitrilative cyanation of aryl boronic acids with dialkylmalononitriles, the present reaction avoids retro‐Thorpe collapse of the intermediate addition product through the use of a milder base. The reaction was amenable to a variety of aryl boronic acids and disubstituted malononitriles, providing a diverse array of β‐ketonitriles. The products could be further derivatized to valuable chiral α,α‐disubstituted‐β‐aminonitriles through addition reactions to the corresponding N ‐tert ‐butanesulfinyl imines. 相似文献
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A series of N‐aryl 2‐alkenamides were produced efficiently by treating N‐aryl 3‐(phenylsulfonyl)‐propanamides with potassium tert‐butoxide in THF at 0°C. With out isolation, it was further treated with an additional equivalent of potassium tert‐butoxide and allyl bromide to give N‐allyl N‐aryl 2‐alkenamides in one pot in good yields. Followed by a ring‐closing metathesis reaction, these N‐allyl N‐aryl 2‐alkenamides were respectively converted into corresponding N‐aryl α,β‐unsaturated γ‐lactams in moderate yields. 相似文献
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Guangying Tan Yimin Wu Yang Shi Jingsong You 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(22):7518-7522
The hydroformylation of alkynes is a fundamental and important reaction in both academic research and industry. Conventional methods focus on the conversion of alkynes, CO, and H2 into α,β‐unsaturated aldehydes, but they often suffer from problems associated with operation, regioselectivity, and chemoselectivity. Herein, we disclose an operationally simple, mild, and syngas‐free rhodium‐catalyzed reaction for the hydroformylation of alkynes via formyl and hydride transfer from an alkyl aldehyde. This synthetic method uses inexpensive and easy‐to‐handle n‐butyraldehyde to overcome the challenge posed by the use of syngas in traditional approaches and employs a commercially available catalyst and ligand to transform a broad range of internal alkynes, especially alkynyl‐containing complex molecules, into versatile stereodefined α,β‐unsaturated aldehydes with excellent chemo‐, regio‐, and stereoselectivity. 相似文献
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The mass spectra of a series of N‐aryl α,β‐unsaturated γ‐lactams were studied. Besides the molecular ion, the three characteristic fragments such as [M+‐29], [M+‐55], and [M+‐82] were commonly found in a series of N‐Aryl α,β‐unsaturated γ‐lactams in EI/MS. Further more the mechanism for the interpretation of these fragments is also de scribed. 相似文献
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Johannes Schranck Mia Burhardt Christoph Bornschein Dr. Helfried Neumann Prof. Dr. Troels Skrydstrup Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9534-9538
A carbonylative α‐arylation process employing unactivated nitriles for the first time is described. The reaction tolerates a range of (hetero)aryl iodides and several nitrile coupling partners. No prefunctionalization of the nitriles is necessary and the resulting β‐ketonitriles are obtained in good to excellent yields. The methodology also allows for a convenient 13C‐labelling of the generated carbonyl moiety. 相似文献
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The [Cu(acac)2]‐catalyzed reactions of α,β‐unsaturated carboxamides with dimethyl diazomalonate yielded dihydrofuran derivatives by a 1,5‐electrocyclic reaction at C(β), and butadiene derivatives by carbene addition reaction at C(α) (Schemes 4 and 5; Table). Phenyl substituents at the N‐atom of the amides seem to be effective on the reaction pathways (Table). 相似文献
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Condensation of aromatic aldehydes with cyclopentanone and cyclohexanone using amino‐functionalized ionic liquid, 1‐aminoethyl‐3‐methyl tetrafluoroborate as solvent and catalyst was successfully performed for preparation of α,α′‐bis(substituted benzylidene)cycloalkanones. The catalyst can be recovered and reused for at least three times without apparently lose of activity. The process is simple, environmentally benign and proceeds in excellent yields. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(5):1391-1395
A general asymmetric route for the one‐step synthesis of chiral β‐branched amides is reported through the highly enantioselective isomerization of allylamines, followed by enamine exchange, and subsequent oxidation. The enamine exchange allows for a rapid and modular synthesis of various amides, including challenging β‐diaryl and β‐cyclic. 相似文献
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Mannepalli Lakshmi Kantam Vura Bala Subrahmanyam Kota Balaji Shiva Kumar Gopaladasu T. Venkanna Bojja Sreedhar 《Helvetica chimica acta》2008,91(10):1947-1953
Rhodium fluoroapatite (RhFAP) is an efficient catalyst for conjugate addition of organoboron reagents to α,β‐unsaturated carbonyl compounds. A variety of arylboronic acids and α,β‐unsaturated carbonyl compounds were converted to the corresponding conjugate‐addition products, demonstrating the versatility of the reaction. The reaction is highly selective. RhFAP was recovered quantitatively by simple filtration, and reused for four cycles. 相似文献
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Ya‐Li Chang Chi‐Lin Chung Fang‐Wen Wu Huey‐Min Wang Rei‐Sheu Hou Iou‐Jiun Kang Ling‐Ching Chen 《中国化学会会志》2010,57(2):149-152
Iodobenzene‐catalyzed synthesis of α‐azidoketones and α‐thiocyanatoketones from aryl ketones with MCPBA as a cooxidant is described. The method is simple, rapid and practical, generating α‐azidoketones and α‐thiocyanatoketones from the aryl ketone without isolation of α‐tosyloxyketones in good to excellent yields. 相似文献
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