Enantioselective Construction of All-Carbon Quaternary Centers by Branch-Selective Pd-Catalyzed Allyl–Allyl Cross-Coupling
作者:Ping Zhang、Hai Le、Robert E. Kyne、James P. Morken
DOI:10.1021/ja2039248
日期:2011.6.29
The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbonquaternarycenters in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3'-reductive elimination of bis(η(1)-allyl)palladium intermediates. Strategies for distinguishing the
Synergistic Peptide and Gold Catalysis: Enantioselective Addition of Branched Aldehydes to Allenamides
作者:Leo D. M. Nicholls、Helma Wennemers
DOI:10.1002/chem.202103197
日期:2021.12.15
A synergistic combination of a tripeptide and a gold complex catalyzes the enantioselectiveaddition between branchedaldehydes and allenamides to furnish synthetically versatile γ,δ-enamide aldehydes with a fully substituted stereogenic center. Mechanistic studies offered key insights into the role of the peptide and acid/base additives.
Construction of All‐Carbon Chiral Quaternary Centers through Cu
<sup>I</sup>
‐Catalyzed Enantioselective Reductive Hydroxymethylation of 1,1‐Disubstituted Allenes with CO
<sub>2</sub>
construction of all-carbon chiral quaternary centers through reductive hydroxymethylation of 1,1-disubstituted allenes with CO2 has been developed. In the presence of a copper/Mandyphos catalyst, CO2 is transformed into an alcohol oxidation level by an asymmetric reductive C-C bond formation with allenes by using hydrosilane (HSi(OMe)2 Me) as a reductant. The resulting chiral homoallylic alcohols are
Enantioselective construction of <i>ortho</i>-substituted benzylic quaternary centers using a phenanthroline-Pd catalyst
作者:Masafumi Tamura
DOI:10.1039/d2ob01743a
日期:——
addition of ortho-substituted arylboronic acids to cyclic enones was developed. The addition of various ortho-substituted arylboronic acid to β-substituted cyclic enones, via catalysis with a chiral phenanthroline-Pd complex, formed cyclic ketone products bearing ortho-substituted benzylic all-carbon quaternarycenters with good yields and high enantioselectivity.