We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetriccyclopropene “hydronitronylation” process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic
Regioselective Diboron-Mediated Semireduction of Terminal Allenes
作者:Ashley M. Gates、Webster L. Santos
DOI:10.1055/s-0039-1690207
日期:2019.12
A method for the regioselective reduction of the terminaldoublebond of 1,1-disubstituted allenes has been developed. In the presence of a palladium catalyst, tetrahydroxydiboron and stoichiometric water, allene semireduction proceeds in high yield to afford Z-alkenes selectively.
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
An asymmetric hydrophosphination of 3,3-disubstituted cyclopropenes catalyzed by Cu(I)-(R,R)-QUINOXP* is developed, affording a series of phosphine derivatives in high to excellent diastereo- and enantioselectivities.
开发了 Cu(I)-( R , R )-QUINOXP*催化的 3,3-二取代环丙烯的不对称氢膦化反应,提供了一系列具有高至优异的非对映选择性和对映选择性的膦衍生物。
Copper-Catalyzed Hydroamination: Enantioselective Addition of Pyrazoles to Cyclopropenes
作者:Minghao Wang、Julie C. Simon、Mengfei Xu、Stephanie A. Corio、Jennifer S. Hirschi、Vy M. Dong
DOI:10.1021/jacs.3c02971
日期:2023.7.12
Chiral N-cyclopropyl pyrazoles and structurally related heterocycles are prepared using an earth-abundant copper catalyst under mild reaction conditions with high regio-, diastereo-, and enantiocontrol. The observed N2:N1 regioselectivity favors the more hindered nitrogen of the pyrazole. Experimental and DFT studies support a unique mechanism that features a five-centered aminocupration.