Synthesis of 1-Amino-2<i>H</i>-quinolizin-2-one Scaffolds by Tandem Silver Catalysis
作者:Xiao-Long Min、Chao Sun、Ying He
DOI:10.1021/acs.orglett.8b03935
日期:2019.2.1
An efficient tandem cycloisomerization–amination reaction catalyzed by silver is described. This rapid and atom-economic reaction delivered 1-amino-2H-quinolizin-2-one scaffolds in high yields under mild conditions. The reaction could be extended to an asymmetric version albeit with moderate enantioselective excess of the products. In addition, the products can be easily reduced into various azabicycles
Rh-Catalyzed Enantioselective [2 + 2] Cycloaddition of Alkynyl Esters and Norbornene Derivatives
作者:Takanori Shibata、Kyoko Takami、Ai Kawachi
DOI:10.1021/ol060055r
日期:2006.3.1
[reaction: see text] The enantioselective [2 + 2] cycloaddition of alkynes possessing an ester functionality and norbornene derivatives proceeded efficiently using a chiral rhodium catalyst. The chiral tri- and tetracyclic cyclobutenes were obtained in moderate to high ee.
cobalt(III)-catalyzed, redox-neutral, intermolecular carboamination of propiolates and bicyclic alkenes was developed. This non-annulative coupling strategy features atom economy, high regioselectivity, good yields, and functional groups tolerance. Such a carboamination reaction was applied to modified phenolsfrom the corresponding phenols under mild conditions.
A gold(I) autotandem catalysis protocol is reported for the de novo synthesis of densely substituted pyrazolines and dihydropyridines from the corresponding imine derivatives in a highly regioselective fashion via a one-pot aza-enyne metathesis/6π-electrocyclization sequence. The substituents on the nitrogen atom of the imine perfectly control the reaction pathways from the pivotal 1-azabutadiene intermediate;
the presence of TMSCN and an alcohol additive are catalyzed by nucleophilicphosphines. The trisubstituted E-olefin products of anti-addition of hydrogen cyanide to the alkyne are produced with high regio- and stereoselectivity. The alcohol additive reacts with TMSCN to produce hydrogen cyanide in situ. Ynoic acids undergo the phosphine catalyzed hydrocyanation in the presence of TMSCN under aprotic