Transition-Metal-Free α-Arylation of β-Keto Amides via an Interrupted Insertion Reaction of Arynes
摘要:
Direct alpha-arylation reactions of secondary beta-keto amides with arynes, generated by fluoride-induced elimination of ortho-silyl aryltriflates, are described. The transformation proceeds via an interrupted insertion reaction of arynes and leads to densely functionalized aromatic compounds exhibiting a chiral 'all carbon' quaternary center under transition-metal-free conditions. An organocatalytic asymmetric version of the reaction also proved possible, affording the proof of concept that arynes can be involved in enantioselective transformations.
Origin of the Enantioselectivity in Organocatalytic Michael Additions of β-Ketoamides to α,β-Unsaturated Carbonyls: A Combined Experimental, Spectroscopic and Theoretical Study
作者:Adrien Quintard、Diana Cheshmedzhieva、Maria del Mar Sanchez Duque、Anouk Gaudel-Siri、Jean-Valère Naubron、Yves Génisson、Jean-Christophe Plaquevent、Xavier Bugaut、Jean Rodriguez、Thierry Constantieux
DOI:10.1002/chem.201404481
日期:2015.1.7
The organocatalytic enantioselective conjugate addition of secondary β‐ketoamides to α,β‐unsaturated carbonyl compounds is reported. Use of bifunctional Takemoto’s thiourea catalyst allows enantiocontrol of the reaction leading either to simple Michael adducts or spirocyclic aminals in up to 99 % ee. The origin of the enantioselectivity has been rationalised based on combined DFT calculations and kinetic