A ring closing enyne metathesis for the synthesis of a series of unsaturated cyclic sulfones is described. The reaction proceeds most effectively with the N-heterocyclic ruthenium carbene catalysts and the rate of reaction depends on the identity of the alkynyl substituent.
One‐Pot Synthesis of 2‐Aminothiophenes by Au(I)‐Catalyzed Cascade Reaction Including Hydrothiolation, Thio‐Claisen Rearrangement, and Cycloisomerization
作者:Yoshihiro Oonishi、Yukiko Ueda、Yoshihiro Sato
DOI:10.1002/adsc.202400249
日期:2024.7.2
The cascade reaction of ynamides with propargyl thiols by Au(I) catalysis involving regioselective hydrothiolation, thio‐Claisen rearrangement, and cycloisomerization to generate 2‐aminothiophenes in a one‐pot manner is described. In this reaction, the selection of reaction temperature is crucial, with the initial step, namely hydrothiolation, conducted at a low temperature (40°C), followed by the
Precatalyst‐Enabled Selectivity: Enantioselective NiH‐Catalyzed
<i>anti</i>
‐Hydrometalative Cyclization of Alkynones to
<i>Endo</i>
‐ and Heterocyclic Allylic Alcohols
作者:Xiao‐Wen Zhang、Ming‐Hui Zhu、Hai‐Xiang Zeng、Qi‐Yang Li、Wen‐Bo Liu
DOI:10.1002/anie.202110815
日期:2021.12.20
AbstractA highly enantioselective NiH‐catalyzed hydrocyclization of alkynones with unparalleled anti‐ and endocyclic selectivities is described. The choice of the precatalysts has significant influence in tuning the regio‐ and enantioselectivity. Using Ni(OTs)2/Phox as a precatalyst and (EtO)2MeSiH as a hydride source, an array of enantioenriched O‐, N‐, and S‐containing heterocyclic tertiary allylic alcohols are obtained in 24–81 % yields with 80:20–99:1 er. Mechanistic investigations and synthetic application are also carried out. This study represents an efficient access to a set of allylic alcohols that are unable to access by the state‐of‐the‐art coupling reactions.
Copper-Free Intramolecular Alkyne–Azide Cycloadditions Leading to Seven-Membered Heterocycles
作者:Míriam Sau、Carles Rodríguez-Escrich、Miquel A. Pericàs
DOI:10.1021/ol201869y
日期:2011.10.7
Treatment of alk-2-ynyl derivatives of enantiopure phenylglycidol with NaN(3) triggers a cascade reaction consisting of stereospecific and regioselective epoxide ring opening followed by intramolecular azide-alkyne cycloaddition under strictly metal-free conditions. This simple one-pot procedure allows a fast buildup of molecular complexity, generating a wide array of triazolooxazepinols, triazolodiazepinols, and triazolothiazepinols.