Rhodium-Catalyzed 1,4-Addition of Arylboronic Acids to α,β-Unsaturated Carbonyl Compounds: Large Accelerating Effects of Bases and Ligands
作者:Ryoh Itooka、Yuki Iguchi、Norio Miyaura
DOI:10.1021/jo0207067
日期:2003.7.1
phosphine derivatives. The reaction was further accelerated in the presence of KOH, thus allowing the 1,4-addition even at 0 degrees C. A cationic rhodium(I)-(R)-binap complex, [Rh(R-binap)(nbd)]BF(4), catalyzed the reaction at 25-50 degrees C in the presence of Et(3)N with high enantioselectivities of up to 99% ee for alpha,beta-unsaturated ketones, 92% for aldehydes, 94% for esters, and 92% for amides.
Palladium and a simple chiral amine are used as co‐catalysts for the enantioselective conjugate addition of aryl boronic acids to α,β‐unsaturated aldehydes (see scheme). The synthetic utility of this co‐catalyzed reaction was demonstrated in the short total syntheses of (R)‐(−)‐curcumene and 4‐aryl‐2‐ones.
Developing a Modern Approach To Account for Steric Effects in Hammett-Type Correlations
作者:Celine B. Santiago、Anat Milo、Matthew S. Sigman
DOI:10.1021/jacs.6b08799
日期:2016.10.12
The effects of aryl ring ortho-, meta-, and para-substitution on site selectivity and enantioselectivity were investigated in the following reactions: (1) enantioselective Pd-catalyzed redox-relay Heck reaction of arylboronic acids, (2) Pd-catalyzed β-aryl elimination of triarylmethanols, and (3) benzoylformate decarboxylase-catalyzed enantioselective benzoin condensation of benzaldehydes. Through
A 1,4-addition of triarylbismuths to cyclic and acyclic enones was carried out in aqueous methanol in the presence of a chiral phosphine–dicationic palladium(II) complex. Palladium complexes of (S,S)-chiraphos or (S,S)-dipamp gave optically active β-arylketones of up to 95% ee.