170938-19-9Relevant academic research and scientific papers
Cobalt-Catalyzed Allylic Alkylation Enabled by Organophotoredox Catalysis
Takizawa, Koji,Sekino, Tomoyuki,Sato, Shunta,Yoshino, Tatsuhiko,Kojima, Masahiro,Matsunaga, Shigeki
supporting information, p. 9199 - 9203 (2019/06/04)
Co-catalyzed allylic substitution reactions have received little attention, arguably because of the lack of any known advantage of Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective Co-catalyzed allylic alkylation using an in situ catalyst activation by organophotoredox catalysis. This noble-metal-free catalytic system exhibits unprecedentedly high reactivities and regioselectivities for the allylation with an allyl sulfone, for the first time, representing the unique synthetic utility of the Co-catalyzed method compared to the related Rh- and Ir-catalyzed reactions.
Rhodium-Catalyzed Asymmetric N?H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (?)-Chaetominine
Zhou, Yirong,Breit, Bernhard
, p. 18156 - 18160 (2017/12/13)
An unprecedented asymmetric N?H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo-, regio-, and enantioselectivities with broad functional group compatibility. Furthermore, this newly developed strategy was applied as key step in the first enantioselective formal total synthesis of (?)-chaetominine.
Substituent effects on the amination of racemic allyl carbonates using commercially available chiral rhodium catalysts
Atallah, Timothy,Blankespoor, Ronald L.,Homan, Philip,Hulderman, Chase,Samas, Brian M.,Van Allsburg, Kurt,Vrieze, Derek C.
, p. 5795 - 5798 (2013/10/01)
In the presence of commercially available chiral rhodium catalysts, a competitive benzy lamination of racemic allyl carbonates, substituted with p-X-Ph groups, shows that the reaction proceeds faster with substituents (X) that are more electron-withdrawing. Mechanistic implications of these results are discussed.
Sequential catalytic isomerization and allylic substitution. Conversion of racemic branched allylic carbonates to enantioenriched allylic substitution products
Shekhar, Shashank,Trantow, Brian,Leitner, Andreas,Hartwig, John F.
, p. 11770 - 11771 (2007/10/03)
A catalytic protocol for the conversion of readily accessible racemic, branched aromatic allylic esters to branched allylic amines, ethers, and alkyls has been developed. Palladium-catalyzed isomerization of branched allylic esters to terminal allylic esters, followed by sequential iridium-catalyzed allylic substitution, gave the branched allylic products in good yield with high regioisomeric and enantiomeric selectivity. Both electron-rich and electron-poor branched allylic esters gave products in >90% ee. High enantiomeric excesses were also observed for the products from the reactions of 2-thienyl acetates and dienyl carbonates. Copyright
Regiocontrol and Stereoselectivity in Tungsten-Bipyridine Catalysed Allylic Alkylation
Lehmann, Juerg,Lloyd-Jones, Guy C.
, p. 8863 - 8874 (2007/10/03)
Tungsten-bipyridine complexes, generated in situ, catalyse the allylic alkylation of isocinnamyl methyl carbonate by dimethyl sodiomalonate with complete syn-stereoselectivity.When para substituted aryl-allyl methyl carbonates are employed, the regioselectivity correlates with Swain-Lupton parameters.Cross-over experiments demonstrate that the reactions do not proceed via the conventional 0> -> II allyl>+ -> 0 allyl-Nu> catalytic cycle.
