enantioselective Negishi cross‐coupling reaction, and the first arylation of α‐halo esters with arylzinc halides, are disclosed. Employing a cobalt‐bisoxazoline catalyst, various α‐arylalkanoic esters were synthesized in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield). A diverse range of functional groups, including ether, halide, thioether, silyl, amine, ester, acetal, amide, olefin
Regioselective 2-alkylation of indoles with α-bromo esters catalyzed by Pd/P,P=O system
作者:Wei Tian、Bowen Li、Duanshuai Tian、Wenjun Tang
DOI:10.1016/j.cclet.2021.06.091
日期:2022.1
A palladium-catalyzed 2-alkylation of indoles with α-bromoesters is developed by employing a P,P=O ligand. The method features excellent regioselectivities, mild reaction conditions, and good functional group compatibility. The employment of the P,P=O ligand as well as 4Å molecular sieves were crucial for the success of the transformation. Mechanistic studies indicate the reaction proceed through
cobalt-bisoxazoline catalyst and afforded various α-alkyl-β,γ-unsaturated esters with excellent enantioselectivities and moderate to good yields (≤95% ee and ≤82% yields). The formal synthesis of the Californiaredscalepheromone using this method was investigated, and radical clock experiments were performed.
enantioselective synthesis of (R)‐cinacalcet with 99% enantiomericexcesses (ee) has been achieved. The main strategies of the approach include a gram‐scale cobalt‐catalysed asymmetric cross‐coupling of racemic ester with arylzinc reagent, Hoffman‐type rearrangement of acidamide, the amidation of chiral amine, and improving the ee of chiral amide from 87% to 99% via recrystallization.