Cooperative C(sp3)–H and C(sp2)–H Activation of 2-Ethylpyridines by Copper and Rhodium: A Route toward Quinolizinium Salts
摘要:
A method for the synthesis of substituted quinolizinium salts from 2-ethylpyridines and alkynes is demonstrated. The transformation is conveniently achieved using 1 mol % of a Rh(III) catalyst along with an excess amount of copper(II) salt. The reaction gives high product yields with broad substrate scope and functional group tolerance. Detailed mechanistic studies suggest that 2-vinylpyridine is formed in situ from 2-ethylpyridine by a copper-promoted C(sp(3))-H hydroxylation, followed by dehydration. Later, a Rh(III)-catalyzed pyridine-directed vinylic C(sp(2))-H activation and annulation with alkynes provided the final product.
Photoenzymatic Hydrogenation of Heteroaromatic Olefins Using ‘Ene’‐Reductases with Photoredox Catalysts
作者:Yuji Nakano、Michael J. Black、Andrew J. Meichan、Braddock A. Sandoval、Megan M. Chung、Kyle F. Biegasiewicz、Tianyu Zhu、Todd K. Hyster
DOI:10.1002/anie.202003125
日期:2020.6.22
selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredoxcatalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where
Decarboxylative trifluoromethylthiolation of lithium pyridylacetates was achieved using N-(trifluoromethylthio)benzenesulfonimide as the electrophilic trifluoromethylthiolation reagent. The reaction afforded the corresponding trifluoromethyl thioethers in good yield. Furthermore, the preparation of lithium pyridylacetates by saponification of the corresponding methyl esters and subsequent decarboxylative
N-cyanoamidine derivatives as anti-influenza agents
申请人:American Home Products Corporation
公开号:US05380734A1
公开(公告)日:1995-01-10
Antiinfluenza A activity was found in compounds of the formula: ##STR1## wherein: X is 2-phenylethyl, 2-furanylmethyl, or ##STR2## where one of R.sup.1 and R.sup.2 is H and the other is phenylamino; Z is --SCH.sub.3 when X is ##STR3## when X is 2-phenylethyl or 2-furanylmethyl; or a pharmaceutically acceptable salt thereof.
Ruthenium-Catalyzed Intermolecular Direct Silylation of Unreactive C(sp<sup>3</sup>)–H Bonds
作者:Wei Li、Xiaolei Huang、Jingsong You
DOI:10.1021/acs.orglett.5b03593
日期:2016.2.19
A Ru-catalyzed intermolecular silylation of unreactive, aliphatic C(sp3)–H bonds has been described for the first time. This protocol features low catalyst loading, a relatively broad substrate spectrum, good functional group tolerance, and no sensitivity to air, which provides a convenient and practical pathway for the construction of C–Si bonds.
Base-promoted, deborylative secondary alkylation of N-heteroaromatic N-oxides with internal gem-bis[(pinacolato)boryl]alkanes: a facile derivatization of 2,2′-bipyridyl analogues
作者:Chiwon Hwang、Woohyun Jo、Seung Hwan Cho
DOI:10.1039/c7cc03731g
日期:——
A base-promoted, secondary alkylation of N-heteroaromatic N-oxides using internal gem-bis[(pinacolato)boryl]alkanes as alkylation reagents is reported. The reaction exhibit broad scope, providing deoxygenated secondary alkylated N-heteroaromatic compounds with high efficiency. The usefulness of the developed protocol is evidenced by sequential direct alkylation of 2,2′-bipyridine-N-oxide.