<i>N</i>,<i>N</i>′-Dioxide/Gd(OTf)<sub>3</sub> Complex-Promoted Asymmetric Aldol Reaction of Silyl Ketene Imines with Isatins: Water Plays an Important Role
A highly diastereo- and enantioselective aldol reaction of isatins with silyl ketene imines was realized by using a chiral N,N′-dioxide/GdIII complex (1 mol %), and with the addition of water, all the reactions completed within 10 min and various β-hydroxy nitriles with adjacent tetrasubstituted stereocenters were obtained in excellent outcomes. The essential role of water was probed, and a possible
A Catalytic Asymmetric Ring‐Expansion Reaction of Isatins and α‐Alkyl‐α‐Diazoesters: Highly Efficient Synthesis of Functionalized 2‐Quinolone Derivatives
Asymmetricexpansion: A catalyticasymmetricring‐expansionreaction of the title compounds occurs in the presence of a Sc(OTf)3 catalyst bearing an N,N′‐dioxide‐based ligand. Highlyfunctionalized2‐quinolonederivatives containing a chiral C4‐quaternary stereocenter were obtained in high yields and high levels of selectivity under mild reaction conditions (see scheme; Tf=trifluoromethanesulfonyl)
Asymmetric Tandem Michael Addition/Interrupted Nef Reactions of Nitromethane with Oxindole-Derived Alkenes: Enantioselective Synthesis of Spiro-polycyclic Oxindoles
作者:Shengshu Liu、Yu-Chen Yang、Yong-Qi Yang、Xin Li、Pengfei Wang、Yin-Long Li、Jun Deng
DOI:10.1021/acs.orglett.4c00919
日期:2024.4.19
and biologically active compounds. Herein, we reported an asymmetric tandem Michaeladdition/interrupted Nef reaction of nitromethane with oxindole-derived alkenes catalyzed by a chiral 2-aminobenzimidazole bifunctional organocatalyst. A series of novel enantiomerically enriched spiro-polycyclic oxindole derivatives bearing an oxime group were synthesized in moderate to excellent isolated yields (up