675608-06-7Relevant academic research and scientific papers
Stereodivergent Allylation of Azaaryl Acetamides and Acetates by Synergistic Iridium and Copper Catalysis
Jiang, Xingyu,Boehm, Philip,Hartwig, John F.
, p. 1239 - 1242 (2018)
We report stereodivergent allylic substitution reactions of allylic esters with prochiral enolates derived from azaaryl acetamides and acetates to form products from addition of the enolates at the most substituted carbon of an allyl moiety with two catalysts, a chiral metallacyclic iridium complex and a chiral bisphosphine-ligated copper(I) complex, which individually control the configuration of the electrophilic and nucleophilic carbon atoms, respectively. By simple permutations of enantiomers of the two catalysts, all four stereoisomers of products containing two stereogenic centers were synthesized individually with high diastereoselectivity and enantioselectivity. A variety of azaaryl acetamides and acetates bearing pyridyl, benzothiazolyl, benzoxazolyl, pyrazinyl, quinolinyl and isoquinolinyl moieties were all found to be suitable for this transformation.
A highly enantio- and diastereoselective molybdenum-catalyzed asymmetric allylic alkylation of cyanoesters
Trost, Barry M.,Miller, John R.,Hoffman Jr., Christopher M.
, p. 8165 - 8167 (2011/07/08)
An efficient molybdenum-catalyzed asymmetric allylic alkylation (Mo-AAA) of cyanoester nucleophiles is reported. A number of highly functionalized branched cyanoesters containing a quaternary carbon stereocenter with a vicinal tertiary stereocenter are obtained. This method generates a number of functionalized cyanoesters in excellent yield and chemoselectivity in good to excellent diastereoselectivity and enantioselectivity.
Effects of catalyst activation and ligand steric properties on the enantioselective allylation of amines and phenoxides
Leitner, Andreas,Shu, Chutian,Hartwig, John F.
, p. 1093 - 1096 (2007/10/03)
(Chemical Equation Presented) The yields, enantioselectivities, and regioselectivities of the reactions of amines and phenoxides with allylic carbonates in the presence of a metallacyclic iridium catalyst were compared. These data show that both preactiva
Regio- and enantioselective allylic amination of achiral allylic esters catalyzed by an iridium-phosphoramidite complex
Ohmura, Toshimichi,Hartwig, John F.
, p. 15164 - 15165 (2007/10/03)
A new catalytic asymmetric process, the iridium-catalyzed enantioselective allylic amination of (E)-cinnamyl and terminal aliphatic allylic carbonates, was developed by exploring complexes of chiral phosphoramidites. The reaction provided branched secondary and tertiary allylic amines in high yields with excellent regio- and enantioselectivity (13 examples over 94% ee). Although the reactions in polar solvent such as DMF, EtOH, and MeOH were fast, they gave low enantiomeric excesses. In contrast, reactions in THF displayed the most suitable balance of rate and enantioselectivity. Both the binaphthol unit and the disubstituted amine in the phosphoramidite affected reactivity and selectivity, and complexes of O,O′-(R)-(1,1′-dinaphthyl-2,2′-diyl)-N,N′-di-(R,R)-1-phenylethylphosphoramidite provided the highest reactivity and selectivity. Primary and cyclic secondary amines reacted at room temperature, and acyclic diethylamine reacted at 50 °C. p-Methoxy-substituted cinnamyl carbonate reacted similarly to the unsubstituted cinnamyl carbonate, but the o-methoxy-substituted substrate gave lower enantiomeric excess. High ee's were also observed for the products from the reaction of furanyl- and alkyl-substituted (E)-allylic carbonates. Copyright
