Cross-Dehydrogenative Coupling between Enamino Esters and Ketones: Synthesis of Tetrasubstituted Pyrroles
摘要:
Tetrasubstituted pyrroles have been synthesized via the cross-dehydrogenative coupling between enamino esters and acetone. Silver carbonate proved to be an effective oxidant, and no transition metal catalyst is necessary.
Oxidative Coupling of Enamines and Disulfides<i>via</i>Tetrabutylammonium Iodide/<i>tert-</i>Butyl Hydroperoxide-Mediated Intermolecular Oxidative C(<i>sp</i><sup><i>2</i></sup>)S Bond Formation Under Transition Metal-Free Conditions
作者:Jiyun Sun、Daisy Zhang-Negrerie、Yunfei Du
DOI:10.1002/adsc.201501099
日期:2016.6.30
compounds with disulfides in the presence of tert‐butyl hydroperoxide and a catalytic amount of tetrabutylammonium iodide conveniently afforded a variety of α‐thioenamine compounds through the intermolecular oxidative C(sp2)S coupling. Incorporating both of the sulfide moieties in the disulfides into the final products under oxidative conditions, this novel approach exhibits the feature of atom efficiency
Novel metal-free, readily available chiral catalytic systems for the enantioselective reduction of keto imines are reported. Different β-imino esters were reduced by trichlorosilane in the presence of 10 mol% of a chiral Lewis base easily obtained in one step only from prolinol, in high yields and in up to 85% enantioselectivity; imines bearing an inexpensive and removable chiral auxiliary, were reduced with complete control of the absolute stereochemistry. The methodology was successfully extended to the stereoselective synthesis of α-amino esters.
Exploring the Oxidative Cyclization of Substituted
<i>N</i>
‐Aryl Enamines: Pd‐Catalyzed Formation of Indoles from Anilines
作者:Julia J. Neumann、Souvik Rakshit、Thomas Dröge、Sebastian Würtz、Frank Glorius
DOI:10.1002/chem.201100631
日期:2011.6.20
The direct Pd‐catalyzed oxidative coupling of twoCH‐bonds within N‐aryl‐enamines 1 allows the efficient formation of differently substituted indoles 2. In this cross‐dehydrogenative coupling, many different functional groups are tolerated and the starting material N‐aryl‐enamines 1 can be easily prepared in one step from commercially available anilines. In addition, the whole sequence can also be
novel palladium-catalyzed regioselective oxidative carbonylation of tri-substituted alkenes with CO and alcohols for the synthesis of α,β-unsaturated esters has been developed. Experimental studies and DFT calculations suggested that the reaction proceeded through alkoxylation of the palladium(II) catalyst, CO and CC double bond migratory insertion, β-(N)H elimination and tautomerization cascade steps