RESUMO
Significant progress in the development of the Morita-Baylis-Hillman (MBH) reaction has been made in the past decade. Many new variations of the MBH reaction have been well exploited, affording unexpected products and novel cyclized adducts in some cases, known as "abnormal MBH reactions". The formation of abnormal MBH adducts depends on the nature of the substrates and the employed catalytic system. This article will summarize recent advances in and mechanistic insights into such "abnormal" MBH reactions, including double-MBH reactions, sila-MBH reactions, abnormal aza-MBH reactions and tandem MBH pathways.
RESUMO
The asymmetric arylation of N-tosylimines with arylboronic acids was realized by using chiral cationic C(2)-symmetric N-heterocyclic carbene (NHC) Pd(2+) diaquo complex 5b as the catalyst in combination with 1.0 equiv of K(3)PO(4) x 3 H(2)O in THF at 4 degrees C in the presence of powdered 4 A MS to afford the corresponding adducts in excellent yields (up to 99%) and good to high enantioselectivities (up to 94% ee).
RESUMO
This paper describes an unexpected and novel nucleophilic phosphine-catalyzed annulation of ethyl (arylimino)acetates to give polysubstituted oxoimidazolidine derivatives in moderate to good yields from simple and easily available starting materials under mild conditions. In this reaction, the addition of methyl vinyl ketone (MVK) is essential to induce the formation of oxoimidazolidines.
Assuntos
Acetatos/química , Imidazolidinas/síntese química , Fosfinas/química , Catálise , TemperaturaRESUMO
The bifunctional chiral phosphine Lewis base (R)-2'-diphenylphosphino-[1,1'-binaphthalene]-2-ol is an effective organocatalyst in the asymmetric aza-MBH reaction of ethyl (arylimino)acetates 1 with MVK and EVK to give the corresponding adducts in moderate to good yields and good to high enantiomeric excesses under mild conditions.