The Novel Activation Model of Multifunction Thiourea Organocatalysts

The novel activation model of multifunction thiourea organocatalysts is examined using density functional theory calculations. The key feature of this model is that the two N-H of thiourea group play different roles in activating substrates, one N-H activates cyclohexenone, and the other N-H and tertiary amine of epiquinine activate the hydroxyl of diphenylphosphine oxide together. More importantly, there is a hydrogen bond between one hydrogen atom in primary amine of catalyst with phenyl ring of diphenylphosphine oxide via a NH-π interaction.