A practical and atom-economic protocol for the stereoselective preparation of various 1,4- and 1,3-diene skeletons through iridium-catalyzed directed olefinic C–H allylation and alkenylation of NH-Ts acrylamides in water was developed. This reaction tolerated a wide scope of substrates under simple reaction conditions and enabled successful gram-scale preparation. Furthermore, an asymmetric variant
catalysis has yet to be demonstrated. The first iridium-catalyzed alkene–alkyne cross-coupling reactions have been realized under ligand- and additive-free conditions. A wide range of acrylamides and alkynes could be used as coupling partners, providing branched (Z,Z)-butadiene skeletons with excellent site- and stereoselectivities. The utility of this approach is also demonstrated by preparative-scale
Iridium-catalyzed hydroalkenylation of conjugated trienes by chelation-assisted alkenyl C–H activation of acrylamides has been demonstrated to produce 1,4,6-trienes atom efficiently with excellent regio- and E/Z selectivities. In contrast, the reaction of benzamides and 1,3,5-trienes proceeds by a tandem hydroarylation of the trienes and cyclization via intramolecular 1,2-addition, providing valuable
Escape from Hydrofunctionalization: Palladium Hydride‐Enabled Difunctionalization of Conjugated Dienes and Enynes
作者:Ziyan Zhang、Vladimir Gevorgyan
DOI:10.1002/anie.202311848
日期:2023.11.20
A palladium hydride-catalyzed difunctionalization of dienes and enynes is reported. This mild protocol harnesses visible light to enhance the hydricity of PdH species, enabling a chemoselectivity switch of the hydropalladation step. This method allows for annulation of dienes and enynes with abundant substrates, such as acrylic acids, acrylic amides, and Baylis–Hillman adducts, toward alkenyl or alkynyl