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.
A highlyenantioselective 1,4-addition of aryltrialkoxysilanes to α,β-unsaturated esters and amides was successfully catalyzed by a chiral rhodiumcomplex generated from [Rh(cod)(MeCN)2]BF4 and (S)-BINAP.
Rhodium/diene-catalyzed asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated Weinreb amides
作者:Ryo Shintani、Takahiro Kimura、Tamio Hayashi
DOI:10.1039/b502921j
日期:——
Rhodium/chiral diene (S,S)-3b complex has been found to effectively catalyze the 1,4-addition of arylboronic acids to α,β-unsaturated Weinreb amides, furnishing useful β-chiral Weinreb amides in high enantioselectivity.
Enantioselective Hydroamidation of Enals by Trapping of a Transient Acyl Species
作者:Pengfei Yuan、Jiean Chen、Jing Zhao、Yong Huang
DOI:10.1002/anie.201803556
日期:2018.7.9
An enantioselective synthesis of β‐chiral amides through asymmetric and redox‐neutral hydroamidation of enals is reported. In this reaction, a chiral N‐heterocyclic carbene (NHC) catalyst reacts with enals to generate the homoenolate intermediate. Upon highly enantioselective β‐protonation through proton‐shuttle catalysis, the resulting azolium intermediate reacts with imidazole to yield the key β‐chiral
Rhodium(I)-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids to α,β-Unsaturated Amides
作者:Satoshi Sakuma、Norio Miyaura
DOI:10.1021/jo010747n
日期:2001.12.1
The conjugate addition of arylboronic acids to alpha,beta-unsaturated amides was carried out in the presence of a chiral rhodium catalyst and an aqueous base. The catalyst prepared in situ from Rh(acac)(CH(2)=CH(2))(2) and (S)-binap provided (R)-N-benzyl-3-phenylbutanamide with 93% ee in the addition of phenylboronic acid to N-benzyl crotonamide. The reaction suffered from incomplete conversion resulting