Catalytic Enantioselective Iodoaminocyclization of Hydrazones
摘要:
The first catalytic enantioselective iodoaminocyclization of beta,gamma-unsaturated hydrazones has been developed with the help of a trans-1,2-diaminocyclohexane-derived bifunctional thiourea catalyst and allows for the direct access to Delta(2)-pyrazolines containing a quaternary stereogenic center in high yield with good enantioselectivity (up to 95% yield and 95:5 er).
TEMPO-Promoted Mono- and Bisimidation of Tertiary Anilines: Synthesis of Symmetric and Unsymmetric <i>N</i>-Mannich Bases
作者:Xiu Juan Xu、Adila Amuti、Wen Jing Hu、Qiaerbati Adelibieke、Abudureheman Wusiman
DOI:10.1021/acs.joc.2c00700
日期:2022.7.15
A TEMPO-promoted method was developed for the synthesis of symmetric bis-N-Mannich bases via sequential activation of two α,α′-amino C(sp3)–H bonds of N,N-dimethylanilines under mild conditions. This methodology was further extended for monoimidation of α-amino-functionalized methylanilines to give unsymmetric N-Mannich bases in good to high yields. Several control experiments were performed, and the
Enantioselective Haloetherification by Asymmetric Opening of <i>meso</i>-Halonium Ions
作者:Ulrich Hennecke、Christian H. Müller、Roland Fröhlich
DOI:10.1021/ol1028805
日期:2011.3.4
A new approach to enantioselective haloetherification reactions via desymmetrization of in situ-generated meso-halonium ions is described. The combination of N-haloamides as a halogen source and sodium salts of chiral phosphoric acids as catalysts can be used for the cyclization of symmetrical ene-diol substrates, yielding the haloetherification products under practical conditions in enantioenriched form.