scholarly journals New amidines from intramolecular cyclization in triflic acid of nitroketene aminals with a tethered phenyl ring

2007 ◽  
Vol 119 (3) ◽  
pp. 259-265 ◽  
Author(s):  
Soro Yaya ◽  
Bamba Fanté ◽  
Siaka Sorho ◽  
Coustard Jean-Marie ◽  
Adima A. Augustin
2000 ◽  
Vol 78 (9) ◽  
pp. 1186-1193
Author(s):  
Cristina Sanchez ◽  
Robert A McClelland

The tamoxifen carbocation (Ph(Ar)C=CPh-CH+-CH3, Ar = 4-Me2NCH2CH2OC6H4) is generated from acetate and sulfate precursors by SN1 ionization in water. The cation exists in (E) and (Z) forms which equilibrate before reaction. The major products are the α-hydroxytamoxifens Ph(Ar)C=CPh-CHOH-CH3, both (E) 64% and (Z) 29%, with the ratio independent of the configuration of the starting ester. Two minor products with a total yield of 7% account for the rest of the products. These have been characterized as indenes derived from intramolecular cyclization, a 4.5% yield of the indene derived from cyclization into the Ar ring with 2.5% due to cyclization into the phenyl ring. Experiments in acid solutions (0.01-0.1 M HCl) starting with pure (E)- or (Z)-α-hydroxytamoxifen reveal that the two alcohols equilibrate. This occurs by H+-catalyzed formation of the carbocation followed by water capture. Occurring about 10-fold slower than this isomerization is an irreversible process resulting in the two indenes. This cyclization will result in the destruction of the α-hydroxytamoxifens upon exposure to acidic conditions and also makes the direct observation of the tamoxifen carbocation under super-acid conditions difficult, if not impossible. The indenes do form in low yield whenever the tamoxifen carbocation is generated from an SN1 precursor. Thus these products could serve as markers for the formation of the tamoxifen carbocation in cellular systems or in in vivo experiments.Key words: carbocation, indene, allylic cation, isomerization.


ChemInform ◽  
2014 ◽  
Vol 45 (52) ◽  
pp. no-no
Author(s):  
Bamba Fante ◽  
Yaya Soro ◽  
Sorho Siaka ◽  
Jerome Marrot ◽  
Jean-Marie Coustard

2014 ◽  
Vol 44 (16) ◽  
pp. 2377-2385 ◽  
Author(s):  
Bamba Fanté ◽  
Yaya Soro ◽  
Sorho Siaka ◽  
Jérôme Marrot ◽  
Jean-Marie Coustard

Synlett ◽  
2014 ◽  
Vol 25 (07) ◽  
pp. 969-974 ◽  
Author(s):  
Bamba Fanté ◽  
Yaya Soro ◽  
Sorho Siaka ◽  
Jérôme Marrot ◽  
Jean-Marie Coustard
Keyword(s):  

2014 ◽  
Vol 44 (22) ◽  
pp. 3328-3336 ◽  
Author(s):  
Bamba Fanté ◽  
Yaya Soro ◽  
Mawa Koné ◽  
Sorho Siaka ◽  
Jean-Marie Coustard

2010 ◽  
Vol 122 (3) ◽  
pp. 582-586 ◽  
Author(s):  
Andrej Matsnev ◽  
Shun Noritake ◽  
Yoshinori Nomura ◽  
Etsuko Tokunaga ◽  
Shuichi Nakamura ◽  
...  

2021 ◽  
Author(s):  
Robert Anthony Denning

The Buchwald-Hartwig reaction has been investigated previously by the Viirre group to show that intramolecular cyclization using palladium and (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl, can instill enantioselectivity. This system was continued to show that steric bulk on the 2’ position on the phenyl ring attached to the nitrogen malonamide can lock the rotation ending in a chiral axis. The diastereomers resulting from this chiral axis can be selectively formed when the substrate is 2-(2-bromobenzyl)-N1,N3-bis(2-(tert-butyl)phenyl)-2-methylmalonamide and using a similar ligand (R)-dicyclohexyl(2'-methoxy-[1,1'-binaphthalen]-2-yl)phosphane with enantio- and diastereoselectivities of 88% and 99% respectively. The work presented in this thesis continues on this class of substrates to include N,1-Di([1,1'-biphenyl]-2-yl)-3-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-3-carboxamide, as well as a newer class of monoamide substrates. The monoamide substrates allowed the interpretation of events occurring in the Buchwald-Hartwig reaction, ultimately showing that the chiral center on the substrate has some control as to the outcome of the chiral axis. Lastly, a timed sampling kinetics experiment was done to investigate if the enantiomers of the starting material were being consumed at different rates or if one diastereomeric product was being produced favourably. The kinetics experiment shows that the system does not have a preference as to the starting material or product being produced.


ChemInform ◽  
2014 ◽  
Vol 45 (45) ◽  
pp. no-no
Author(s):  
Bamba Fante ◽  
Yaya Soro ◽  
Sorho Siaka ◽  
Jerome Marrot ◽  
Jean-Marie Coustard
Keyword(s):  

2021 ◽  
Author(s):  
Robert Anthony Denning

The Buchwald-Hartwig reaction has been investigated previously by the Viirre group to show that intramolecular cyclization using palladium and (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl, can instill enantioselectivity. This system was continued to show that steric bulk on the 2’ position on the phenyl ring attached to the nitrogen malonamide can lock the rotation ending in a chiral axis. The diastereomers resulting from this chiral axis can be selectively formed when the substrate is 2-(2-bromobenzyl)-N1,N3-bis(2-(tert-butyl)phenyl)-2-methylmalonamide and using a similar ligand (R)-dicyclohexyl(2'-methoxy-[1,1'-binaphthalen]-2-yl)phosphane with enantio- and diastereoselectivities of 88% and 99% respectively. The work presented in this thesis continues on this class of substrates to include N,1-Di([1,1'-biphenyl]-2-yl)-3-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-3-carboxamide, as well as a newer class of monoamide substrates. The monoamide substrates allowed the interpretation of events occurring in the Buchwald-Hartwig reaction, ultimately showing that the chiral center on the substrate has some control as to the outcome of the chiral axis. Lastly, a timed sampling kinetics experiment was done to investigate if the enantiomers of the starting material were being consumed at different rates or if one diastereomeric product was being produced favourably. The kinetics experiment shows that the system does not have a preference as to the starting material or product being produced.


ChemInform ◽  
2010 ◽  
Vol 41 (20) ◽  
Author(s):  
Andrej Matsnev ◽  
Shun Noritake ◽  
Yoshinori Nomura ◽  
Etsuko Tokunaga ◽  
Shuichi Nakamura ◽  
...  

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