Palladium Catalyzed Conjugate 1,4-Addition of Organoboronic Acids to α,β-Unsaturated Ketones
作者:Tetsuya Yamamoto、Michiko Iizuka、Tetsuo Ohta、Yoshihiko Ito
DOI:10.1246/cl.2006.198
日期:2006.2
1,4-Addition of arylboronic acids to α,β-unsaturated ketones was smoothly catalyzed by palladium(0) phosphine complexes with chloroform in the presence of base. It is remarked that the palladium(0) complexes have no catalytic activity in the absence of chloroform. The reaction proceeded without β-hydride elimination.
Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform
作者:Tetsuya Yamamoto、Michiko Iizuka、Hiroto Takenaka、Tetsuo Ohta、Yoshihiko Ito
DOI:10.1016/j.jorganchem.2008.12.032
日期:2009.4
Arylboronic acids react with aldehydes and α,β-unsaturatedcarbonylcompounds in the presence of a base and a catalytic amount of a palladium(0) complex with chloroform, affording the corresponding addition products in good yields, and chiral benzhydrol was obtained with up to 43% e.e. using (S,S)-bppm as a ligand. General palladium complexes have no catalytic activity without chloroform. Because chloroform
N-Tosylated α, β-unsaturatedamides and lactams undergo facile conjugate addition with R2CuLi or RMgX/CuI (cat.). Stereoselective synthesis of trans-β,γ-dialkyl-γ-lactams can be achieved by this procedure. The resulting N-tosylamide moiety is further transformed to alcohol and several carbonyl compounds by way of reduction or nucleophillic displacement.
New asymmetricconjugatereduction of beta,beta-disubstituted alpha,beta-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2-one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60 degrees C in 95 % ee and 98 % ee, respectively
Asymmetric Umpolung Hydrogenation and Deuteration of Alkenes Catalyzed by Nickel
作者:Siyu Guo、Xiuhua Wang、Jianrong Steve Zhou
DOI:10.1021/acs.orglett.0c00112
日期:2020.2.7
enantioselectivity, using acetic acid or water as the hydrogen source and indium powder as electron donor. The scope of alkenes herein include α,β-unsaturated esters, nitriles, and ketones as well as allylicalcohols. Asymmetric deuteration of α,β-unsaturated esters is also achieved with deuterated water, the cheapest deuterium source.