The mechanism studies of catalytic chemoselective conjugate addition of amino alcohols to α,β-unsaturated ester

The competing mechanisms of silver-/aminolithium-catalyzed hydrofunctionalization of α,β-unsaturated ester with an amino alcohol have been systematically studied with the DFT methods. Here, the acidity of a weaker nucleophile OH group of an amino alcohol is significantly higher than that of NH2 group, so it is easy to deprotonate by Ag(HMDS)/dppe. However, the generated Ag–O bond is more stable than the corresponding Ag–N bond. Therefore, the OH group shows higher reactivity than the NH2 group in the presence of a Lewis acid/Bronsted base pair catalyst. Then, α,β-unsaturated esters can be inserted into corresponding Ag–O bonds to obtain alkyl silver species. Alkyl silver can be protonated by bis(trimethylsilyl)amines to obtain hydrogen functionalized products and regenerate silver amino active compounds Ag(HMDS)/dppe.