Hydrotalcite-supported palladium nanoparticles as catalysts for the hydroarylation of carbon–carbon multiple bonds
作者:A. Di Nicola、A. Arcadi、K. Gallucci、V. Mucciante、L. Rossi
DOI:10.1039/c7nj04046f
日期:——
alkenes with aryl iodides under air in MeCN. The reaction of tertiary propargylic alcohols (1) with aryl iodides (2) yields, stereoselectively, γ,γ-diarylallylic alcohols (3) in moderate to high yields and high selectivity. Also, the HT/Pd hydroarylation reaction with aryl iodides was attempted on norbornene and α,β-unsaturated ketones affording, respectively, exo-aryl bicyclo[2.2.1]heptanes and β-aryl ketones
Chemo-, regio-, and stereoselective Heck–Matsuda arylation of allylic alcohols under mild conditions
作者:Tohasib Yusub Chaudhari、Asik Hossian、Manash Kumar Manna、Ranjan Jana
DOI:10.1039/c5ob00235d
日期:——
Heck arylation with allylic alcohol is extremely challenging due to chemo-, regio-, and stereoselective scrambling. Here we report a mild protocol for the alcohol selective β- and α-arylation of allylic and cinnamyl alcohols respectively with aryldiazonium salts. The steric and electronic parameters of the alkene play a prominent role in the regioselectivity.
Asymmetric Traceless Petasis Borono‐Mannich Reactions of Enals: Reductive Transposition of Allylic Diazenes
作者:Yao Jiang、Regan J. Thomson、Scott E. Schaus
DOI:10.1002/anie.201708784
日期:2017.12.22
The traceless Petasis borono‐Mannich reaction of enals, sulfonylhydrazines, and allylboronates, catalyzed by chiral biphenols, results in an asymmetric reductivetransposition of the in situ generated allylic diazene. Acyclic 1,4‐diene products bearing either alkyl‐ or aryl‐substituted benzylic stereocenters are afforded in excellent yields and enantiomeric ratios of up to 99:1. The use of crotylboronates
Chiral dihydrobenzo[1,4]oxazines as catalysts for the asymmetric transfer-hydrogenation of α,β-unsaturated aldehydes
作者:Christian Ebner、Andreas Pfaltz
DOI:10.1016/j.tet.2011.10.051
日期:2011.12
A new class of organocatalysts based on the structure of 2,3-dihydrobenzo[1,4]oxazine was prepared and applied in the enantioselective transfer-hydrogenation of α,β-unsaturatedaldehydes with Hantzsch ester as hydride donor. These catalysts proved to be particularly effective for the conjugate reduction of β,β-diaryl-substituted acrylaldehydes leading to saturated aldehydes bearing a stereogenic center
and dioxygen serve as oxidants in highly stereoselective oxidative Pd‐catalyzed Heck arylations in which aryl boronicacids are used to synthesize triarylalkyl‐substituted olefins. The reactions occur under very mild conditions at room temperature. As an example, the threefold sequential arylation of methyl acrylate is the crucial step in the stereoselective synthesis of Z‐Tamoxifen.