1422985-19-0Relevant academic research and scientific papers
Restricted conformation of a hydrogen bond mediated catalyst enables the highly efficient enantioselective construction of an all-Carbon quaternary stereocenter
Xu, Weici,Shen, Xiang,Ma, Qiao,Gong, Lei,Meggers, Eric
, p. 7641 - 7646 (2016)
A highly active catalyst for the enantioselective Friedel? Crafts alkylation of indoles with β,β-disubstituted nitroalkenes is reported, allowing catalyst loadings down to 0.05 mol % for this challenging transformation, providing useful synthetic building blocks with an all-carbon quaternary stereocenter. The catalyst is based on a bis-cyclometalated iridium(III) complex as a structural template, and through the ligand sphere it forms hydrogen bonds with the two substrates. Starting from a previous design (Angew. Chem. Int. Ed. 2013, 52, 14021), the catalyst was rendered C2-symmetrical in order to maximize the atom economy of this catalyst scaffold (two catalytic centers per iridium complex), and, most importantly, rational design was applied to restrict the conformational freedom of a key hydrogen bond acceptor, being responsible for activating the indole nucleophile and bringing it in an ideal position for the presumed ternary transition state.
Highly enantioselective construction of CF3-bearing all-carbon quaternary stereocenters: Hiral spiro-fused bisoxazoline ligands with 1,1′-binaphthyl sidearm for asymmetric Michael-type Friedel-Crafts reaction
Bao, Robert Li-Yuan,Fu, Kang,Shi, Lei
, (2021/11/27)
A novel class of chiral spiro-fused bisoxazoline ligands possessing a deep chiral pocket was prepared. The developed ligands have been employed in the nickel-catalyzed highly enantioselective Michael-type Friedel-Crafts reaction, affording the products bearing a trifluoromethylated all-carbon quaternary stereocenter with moderate to excellent yields (up to 99%) and good to excellent enantioselectivies (up to > 99.9% ee). Moreover, a proposed model of chiral pocket revealed that the attack of indole from the Re-face of β-CF3-β-disubstituted nitroalkene was favorable.
Highly enantioselective construction of trifluoromethylated all-carbon quaternary stereocenters via nickel-catalyzed friedel-crafts alkylation reaction
Gao, Jian-Rong,Wu, Hao,Xiang, Bin,Yu, Wu-Bin,Han, Liang,Jia, Yi-Xia
, p. 2983 - 2986 (2013/04/10)
A highly enantioselective Friedel-Crafts alkylation reaction of indoles with β-CF3-β-disubstituted nitroalkenes was achieved using a Ni(ClO4)2-bisoxazoline complex as a catalyst, which afforded indole-bearing chiral compou
