Theoretical study with DFT on the mechanism of visible light-driven β-functionalization of aldehydes
Abstract We present results of density functional theory (DFT) study on the mechanism of photo-organocatalytic β-functionalization of aldehydes with Michael acceptors. The plausible mechanism afforded involves three distinct steps: radical generation, radical addition, oxidative hydrogen atom transfer. The region-determining step is the radical addition step which affords α- or β-radical addition adduct through α-/β-transition states with different barrier. In the reduction step of radical addition adduct, the calculation results support our proposal that oxidative hydrogen atom transfers (HAT) from enamine to the radical addition adduct, generates a neutral intermediate and β-enaminylradical, the latter of which thereafter participates in the previous step of radical addition to form β- intermediate. Our result is in satisfactory accordance with the experimental observation.
This essay consists of some clarifying remarks on the doctrine of double effect (DDE). After providing a contemporary formulation of the doctrine we put special emphasis on the distinction between those aspects of an action plan that are intended and those that are merely foreseen (the I/F distinction). Making use of this distinction is often made difficult in practice because salient aspects of the action plan exhibit a felt “closeness” to one another that is difficult if not impossible to articulate with the precision we might like. The essay goes on to examine an especially adroit criticism of DDE best articulated by J. J. Thomson. We conclude with a brand new double effect case (new to the philosophical literature anyway) taken from medicine and Roman Catholic pastoral ministry.