LAUSR

Abstract Density functional theory (DFT) calculations show that regardless of using BrettPhos or (o-OMePh)3P ligand, the Pd-catalyzed synthesis of both 1,3- and 1,4-enynes from hydroalkynylations of allenamides proceeds through the hydropalladation mechanism, rather than the carbopalladation mechanism, as proposed for the formation of 1,4-enyne in the experimental study. BrettPhos ligand favors the formation of 1,4-enyne through anti-Markovnikov addition of Pd H bond to the C C double bond, while (o-OMePh)3P ligand leads to the 1,3-enyne through the Markovnikov addition. The palladium catalysis also promotes the isomerization of E-1,3-enyne to its Z-isomer, rationalizing the observed stereoselectivity.