Synthesis of Lactams by Isomerization of Oxindoles Substituted at C-3 by an ω-Amino Chain
摘要:
Oxindoles substituted at N-1 by electron-withdrawing groups and at C-3 by omega-amino chains of various lengths undergo mild and easy isomerization to new 5- to 12-membered lactams in good yields (3096%). As efficient asymmetric syntheses of diversely 3,3-disubstituted oxindoles are currently developed, this isomerization provides a new and valuable access to medium-sized lactams alpha-substituted with a quaternary asymmetric carbon bearing a 2-aminophenyl residue.
Synthesis of Lactams by Isomerization of Oxindoles Substituted at C-3 by an ω-Amino Chain
摘要:
Oxindoles substituted at N-1 by electron-withdrawing groups and at C-3 by omega-amino chains of various lengths undergo mild and easy isomerization to new 5- to 12-membered lactams in good yields (3096%). As efficient asymmetric syntheses of diversely 3,3-disubstituted oxindoles are currently developed, this isomerization provides a new and valuable access to medium-sized lactams alpha-substituted with a quaternary asymmetric carbon bearing a 2-aminophenyl residue.
phase‐transfer reaction system can be applied to highly enantioselectiveconjugateaddition and aldol reactions under the influence of chiral bifunctional ammonium bromides as key catalysts. The structure of the chiral ammonium enolate intermediate is discussed based on the single‐crystal X‐ray structures of relevant ammonium salts and the importance of bifunctional design of catalyst is clearly explained in the