scholarly journals Reactions between Furyl Ketones and Grignard Reagents. III. Suppression of 1,4-Addition of Benzylmagnesium Chloride to Alkyl 2-Furyl Ketones by Voluminous Alkyl Groups at the Carbonyl Carbon.

1980 ◽  
Vol 34b ◽  
pp. 446-448
Author(s):  
Rainer Sjöholm ◽  
Agneta Lundqvist ◽  
Per-Olof Lagerström ◽  
Tamas Bartfai ◽  
Curt R. Enzell
Keyword(s):  
Grignard Reagents ◽  
Carbonyl Carbon ◽  
Alkyl Groups

Alkyl 1-[2-(oxido anion)-, 3-, 4-, 5-alkyl substituted]phenyl ketyl radicals

1979 ◽  
Vol 44 (6) ◽  
pp. 1731-1741 ◽  
Author(s):  
Andrej Staško ◽  
Ľubomír Malík ◽  
Alexander Tkáč ◽  
Vladimír Adamčík ◽  
Eva Maťašová
Keyword(s):  
Electron Donor ◽  
Unpaired Electron ◽  
Grignard Reagents ◽  
Slight Effect ◽  
Benzene Nucleus ◽  
Alkyl Groups ◽  
Splitting Constant

Reactions of R2,R3-alkyl substituted 2-hydroxybenzenecarboxylic acids 2-HO-C6H2R2-COOH with Grignard reagents R1MgBr in the presence of nickel give stable aryl alkyl ketyl radicals 2-O--R2-, R3-C6H2-CO--R1 where R1 = CH3, C2H5, C2D5, n-C3H7 and R2,R3 = CH3, C2H5, i-C3H7, t-C4H9. The β protons of ketyl group are equivalent (splitting constant 1.25 mT) and non-equivalent (splitting constants within 0.5 to 1.5 mT) for R1 = methyl and other alkyl groups, respectively. Interaction of the γ protons with the unpaired electron was only observed in the case of R1 = n-propyl (splitting constants about 0.07 mT). The substituents R1 have but slight effect on values of splitting constants of the protons in R2,R3 and vice versa. Also splitting constants of the benzene nucleus (a4H = 0.55 mT, a6H = 0.44 mT) are only slightly affected by the substituents R1,R2,R3, which indicates dominant electron-donor effect of the oxido-anion group eliminating the relatively smaller contributions of the alkyl substituents.

scholarly journals A versatile method for the N, N-dialkylation of aromatic amines via Grignard reactions on N,N-bis(benzotriazolylmethyl)arylamines

1990 ◽  
Vol 68 (3) ◽  
pp. 456-463 ◽  
Author(s):  
Alan R. Katritzky ◽  
Stanislaw Rachwal ◽  
Jing Wu
Keyword(s):  
Alkyl Group ◽  
Aromatic Amines ◽  
Grignard Reagents ◽  
Grignard Reaction ◽  
Aryl Ring ◽  
Alkyl Groups ◽  
Grignard Reactions ◽  
Stepwise Procedure ◽  
High Yields

Grignard reactions of N,N-bis(benzotriazolylmethyl)arylamines afford the corresponding N,N-dialkylarylamines in high yields. Electron-releasing substituents on the aryl ring facilitate the reaction. Arylamines are N,N-dialkylated with two different alkyl groups by a stepwise procedure: N-benzotriazolylmethylation of an amine followed by a Grignard reaction to introduce the first alkyl group, and repetition of the same procedure to introduce the second alkyl group. Grignard reagents derived from 1,4-dihalobutane, upon reaction with N,N-bis(benzotriazolylmethyl)arylamines, give the corresponding N-aryl-hexahydroazepines together with acyclic products. Keywords: azepine, tertiary arylamines.

scholarly journals Effect of uridine protecting groups on the diastereoselectivity of uridine-derived aldehyde 5’-alkynylation

2017 ◽  
Vol 13 ◽  
pp. 1533-1541 ◽  
Author(s):  
Raja Ben Othman ◽  
Mickaël J Fer ◽  
Laurent Le Corre ◽  
Sandrine Calvet-Vitale ◽  
Christine Gravier-Pelletier
Keyword(s):  
Carbonyl Group ◽  
Protecting Groups ◽  
Grignard Reagents ◽  
Group Effect ◽  
Protecting Group ◽  
Alkyl Groups ◽  
Silyl Groups

The 5’-alkynylation of uridine-derived aldehydes is described. The addition of alkynyl Grignard reagents on the carbonyl group is significantly influenced by the 2’,3’-di-O-protecting groups (R1): O-alkyl groups led to modest diastereoselectivities (65:35) in favor of the 5’R-isomer, whereas O-silyl groups promoted higher diastereoselectivities (up to 99:1) in favor of the 5’S-isomer. A study related to this protecting group effect on the diastereoselectivity is reported.

Cu-Catalyzed Conjugate Addition of Grignard Reagents to Thiochromones: An Enantioselective Pathway for Accessing 2-Alkylthiochromanones

Synlett ◽  
2018 ◽  
Vol 29 (15) ◽  
pp. 2071-2075 ◽  
Author(s):  
Qingxiong Yang ◽  
Jun Wang ◽  
Shihui Luo ◽  
Ling Meng
Keyword(s):  
Conjugate Addition ◽  
Grignard Reagents ◽  
Established Method ◽  
Alkyl Groups ◽  
Biological Studies ◽  
First Time

The enantioselective incorporation of alkyl groups in thiochromones was realized for the first time by a Cu/(R,S)-PPF-P t Bu2-catalyzed conjugate addition of Grignard reagents to thiochromones. With this method, a series of 2-methylthiochromanones were obtained in good yields (up to 96% yield) with moderate-to-good ee values (up to 87% ee). The established method expedites the synthesis of a large library of chiral thiochromanones for further synthetic applications and biological studies.

Fe-Catalyzed Conjunctive Cross-Couplings of Unactivated Alkenes with Grignard Reagents

2020 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Cassandra R. Youshaw ◽  
Mingbin Yuan ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Functional Groups ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Turnover Frequency ◽  
Diverse Range ◽  
Cascade Cyclization ◽  
Radical Cascade

The first iron-catalyzed three-component cross-coupling of unactivated olefins with alkyl halides and Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles, alkyl halides, and unactivated olefins bearing diverse functional groups to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

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