An investigation of inattentional blindness using gaze and frequency tagging.

Inattentional blindness (IB) occurs when a salient object presented in plain sight goes unnoticed when its appearance is unexpected. Across two experiments, participants completed a classic dynamic IB task while eye movements and steady-state visual evoked potential (SSVEP) responses were continually recorded. This allowed us to measure the modulation of gaze and brain-based indices of attention during IB. While an SSVEP response to all stimuli including the unexpected object was attained, only gaze measures were able to discriminate noticers from nonnoticers. Experiment 1 used a prototypical sustained IB task and found that gaze toward the unexpected object was largely unrelated to noticing that object. Experiment 2 manipulated the contrast of the target and distractor stimuli, and instead observed a tight concordance between gazing at the unexpected object and reporting its presence. This task-based variability in gaze deployment is consistent with the broader literature and cumulatively delineates the challenges faced in translating lab-based IB research from the bench to the bedside. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Desymmetrization of difluoromethylene groups by C-F bond activation.

Tertiary stereogenic centres containing one fluorine atom are valuable for medicinal chemistry because they mimic common tertiary stereogenic centres containing one hydrogen atom, but they possess distinct charge distribution, lipophilicity, conformation and metabolic stability1-3. Although tertiary stereogenic centres containing one hydrogen atom are often set by enantioselective desymmetrization reactions at one of the two carbon-hydrogen (C-H) bonds of a methylene group, tertiary stereocentres containing fluorine have not yet been constructed by the analogous desymmetrization reaction at one of the two carbon-fluorine (C-F) bonds of a difluoromethylene group3. Fluorine atoms are similar in size to hydrogen atoms but have distinct electronic properties, causing C-F bonds to be exceptionally strong and geminal C-F bonds to strengthen one another4. Thus, exhaustive defluorination typically dominates over the selective replacement of a single C-F bond, hindering the development of the enantioselective substitution of one fluorine atom to form a stereogenic centre5,6. Here we report the catalytic, enantioselective activation of a single C-F bond in an allylic difluoromethylene group to provide a broad range of products containing a monofluorinated tertiary stereogenic centre. By combining a tailored chiral iridium phosphoramidite catalyst, which controls regioselectivity, chemoselectivity and enantioselectivity, with a fluorophilic activator, which assists the oxidative addition of the C-F bond, these reactions occur in high yield and selectivity. The design principles proposed in this work extend to palladium-catalysed benzylic substitution, demonstrating the generality of the approach.