Radical bromination-induced ipso cyclization–ortho cyclization sequence of N-hydroxylethyl-N-arylpropiolamides

2021 ◽  
Author(s):  
Yu-Chao Wang ◽  
Keke Huang ◽  
Xiaojing Lai ◽  
Zhongning Shi ◽  
Jin-Biao Liu ◽  
...  
Keyword(s):  
Radical Bromination

A facile procedure is reported for the synthesis of various 2-bromo-1-phenyl-5,6-dihydro-3H,7aH-benzo[b]pyrrolo[2,1-c][1,4]oxazin-3-ones via a brominative spiro-tricyclization of N-arylpropiolamides in the presence of TBAB and oxone.

Directing Bromination of Piperazine-2,5-diones

1995 ◽  
Vol 48 (7) ◽  
pp. 1379 ◽  
Author(s):  
TW Badran ◽  
CLL Chai ◽  
CJ Easton ◽  
JB Harper ◽  
DM Page
Keyword(s):  
Free Radical ◽  
Methyl Substituent ◽  
Radical Bromination ◽  
Acetyl Group

From intermolecular and intramolecular competition experiments, it has been established that, by comparison with an N-methyl substituent, an N-acetyl group deactivates glycine residues in piperazine-2,5-diones towards free-radical bromination. Combined with the ease of introduction and removal of N-acetyl substituents, the deactivating effect provides a method for regiocontrolled functionalization of these compounds.

ChemInform Abstract: Free-Radical Bromination of Selected Organic Compounds in Water.

ChemInform ◽  
2010 ◽  
Vol 28 (23) ◽  
pp. no-no
Author(s):  
H. SHAW ◽  
H. D. PERLMUTTER ◽  
C. GU ◽  
S. D. ARCO ◽  
T. O. QUIBUYEN
Keyword(s):  
Free Radical ◽  
Organic Compounds ◽  
Radical Bromination

Solvent Dependent Benzylic Radical Bromination of Aromatic Sulfonyl Chlorides

2006 ◽  
Vol 3 (3) ◽  
pp. 191-194 ◽  
Author(s):  
Laura Quartara ◽  
Maria Altamura ◽  
Annalisa Guerri ◽  
Rossano Nannicini ◽  
Martina Gensini ◽  
...  
Keyword(s):  
Sulfonyl Chlorides ◽  
Radical Bromination

Stereoelectronic effects on chemoselectivity in the free radical bromination of arylcyclopropanes

1990 ◽  
Vol 112 (14) ◽  
pp. 5557-5562 ◽  
Author(s):  
James M. Tanko ◽  
Rosemal H. Mas ◽  
N. Kamrudin Suleman
Keyword(s):  
Free Radical ◽  
Stereoelectronic Effects ◽  
Radical Bromination

scholarly journals THE FREE RADICAL BRO MINA TION OF ETHYL PYRIDAZINES: THEORETICAL STUDIES

2014 ◽  
Vol 22 (22) ◽  
pp. 53-60
Author(s):  
I. A. ADEJORO ◽  
R. O. Ogede ◽  
C. U. Ibeji ◽  
O. O. Adeboye
Keyword(s):  
Free Radical ◽  
Rapid Method ◽  
Computational Methods ◽  
Theoretical Studies ◽  
Hartree Fock ◽  
Radical Bromination ◽  
Total Energies ◽  
Pyridazine Derivatives ◽  
Semi Empirical

Theoretical studies on free radical bromination by N-bromosuccinimide were carried out on a range of ethyl-3-methoxy-pyridazine derivatives. The investigations of these reactions performed, in order to develop a convenient and rapid theoretical means of predicting selectivity. The geometry optimizations of the total energies of the reactants and the products were calculated using Semi-empirical; AMI, MNDO, PM3 e Hartree Fock, HF3- 21 G computational methods. The calculation performed using PM3 Hamiltonian gave the best qualitative predictions, thus providing a rapid method for the selectivity of the reactions used in the synthesis of novel heterocyclic analogs of neurotransmitters.

Reactivities of Piperazine-2,5-diones in Radical Bromination Reactions

1996 ◽  
Vol 49 (11) ◽  
pp. 1229 ◽  
Author(s):  
CLL Chai ◽  
DCR Hockless ◽  
AR King
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Chemical Reactivity ◽  
Trans Isomers ◽  
Radical Bromination ◽  
Conformational Effects ◽  
Cis And Trans Isomers ◽  
The Difference ◽  
Cis And Trans

The reactivities of various N,N'- diacetylated piperazine-2,5-diones towards radical bromination reactions are reported. The studies show that glycyl centres of piperazine-2,5-diones are more reactive towards radical bromination reactions compared to α-substituted amino acid centres. In addition, large differences in reactivities were observed for the cis and trans isomers of N,N'-diacetylated alanine anhydride. Single-crystal structure determination of each isomer revealed that conformational effects may account for the difference in chemical reactivity.

Synthesis of Tetrahydroisoquinolines by Visible-Light-Mediated 6-exo-trig Cyclization of α-Aminoalkyl Radicals

Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1825-1829 ◽  
Author(s):  
Michael Grübel ◽  
Christian Jandl ◽  
Thorsten Bach
Keyword(s):  
Crystal Structure ◽  
Direct Electron Transfer ◽  
Metal Catalyst ◽  
Cesium Carbonate ◽  
Reaction Conditions ◽  
Relative Configuration ◽  
Radical Bromination ◽  
Step Procedure ◽  
Michael Acceptors ◽  
High Yields

Starting from the respective tertiary α-silylmethyl amines, the intramolecular cyclization of α-aminoalkyl radicals to Michael acceptors produced tetrahydroisoquinolines. The reaction conditions included the use of 5 mol% of an iridium photoredox catalyst, dimethylformamide as the solvent, and equimolar amounts of water and cesium carbonate as the additives. 13 substrates were synthesized from ortho-alkylbenzaldehydes in a three-step procedure involving a carbonyl condensation, a radical bromination, and a substitution by a secondary α-silylmethyl amine. After optimization of the photocyclization, the reaction delivered tetrahydroisoquinolines in moderate to high yields (41–83%). A facial diastereoselectivity (dr ≅ 80:20) was observed with chiral substrates and a crystal structure provided evidence for the relative configuration of the major diastereoisomer. A catalytic cycle with direct electron transfer to the photoexcited metal catalyst is proposed.

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