Much evidence shows that instruction that actively engages students with learning materials is more effective than traditional, lecture-centric instruction. These "active learning" models comprise an extremely heterogeneous set of instructional methods: they often include collaborative activities, flipped classrooms, or a combination of both. To date, it is unclear whether active learning is more effective if it combines collaboration support with flipped classroom methods. We conducted a quasi-experiment as part of an advanced general chemistry course with 413 undergraduate students. We tested whether active learning is more effective than traditional instruction if it includes collaboration support only or a combination of collaboration support and flipped classrooms. Further, we explored effects on students' attitude. Our results show that only the combination of collaboration support and flipped classroom methods led to significantly higher learning outcomes than traditional instruction. Furthermore, our results reveal potential negative effects of active learning interventions on student attitudes.

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The vicinal fluorofunctionalization of alkenes represents an expedient strategy for converting feedstock olefins into valuable fluorinated molecules and as such has garnered significant attention from the synthetic community; however, current methods remain limited in terms of scope and selectivity. Here we report the site-selective palladium-catalyzed threecomponent coupling of alkenylbenzaldehydes, arylboronic acids, and N-fluoro-2,4,6trimethylpyridinium hexafluorophosphate facilitated by a transient directing group. The synthetically enabling methodology constructs vicinal stereocenters with excellent regio-, diastereo-, and enantioselectivities, forging products that map onto bioactive compounds. Main Text:The incorporation of carbon-fluorine (C-F) bonds into drug molecules can often improve their pharmacokinetic properties, including increasing oral bioavailability, protein binding affinities, and metabolic stability, especially in the case of replacement of benzylic C-H bonds prone to metabolic oxidation 1,2 . As such, the development of strategies that enable the enantioselective formation of C-F bonds has become a major research area of both industrial and academic importance in recent years [3][4][5] . In particular, intermolecular 1,2-carbofluorination of alkenes is an attractive transformation as it allows for the conversion of alkene feedstocks into fluorinated molecules with potential applications in the pharmaceutical, agrochemical, and material sectors 6 ; however, this type of transformation remains challenging to execute due to issues with regio-, stereo-, and chemoselectivity. In early work, the groups of Ma 7 , Gagné 8 , Alexakis 9 , and Gouverneur 10 reported pioneering examples of asymmetric fluorocyclizations of prochiral alkenes, in which a functional group tethered to the alkene reacts in the cyclization process.More recently, Toste and coworkers have reported an elegant series of intermolecular (threecomponent) asymmetric arylfluorination reactions to construct chiral benzyl fluorides using palladium/N,N-ligand systems. This strategy has been used for both 1,1-arylfluorination (where regioselectivity is governed by substrate electronics) 11,12 and 1,2-arylfluorination (where selectivity is governed by substrate directivity) 13 . While the aforementioned work represents a great deal of progress, significant limitations remain. Palladium-catalyzed arylfluorination reactions are sensitive to alkene substitution patterns; for instance, disubstituted alkenes require double activation to enhance reactivity 14 , and no existing methods are able to construct fully substituted C(sp 3 )-F or C(sp 3 )-Ar stereocenters. Additionally, achieving high levels of pathway selectivity for a given substrate class (favoring 1,2-arylfluorination over 1,1-arylfluorination, βhydride elimination, or other side reactions) often requires extensive ligand optimization and the use of potentially synthetically restrictive directing groups 15 .

Metal‐coordinating directing groups have seen extensive use in the field of transition‐metal‐catalyzed alkene functionalization; however, their waste‐generating installation and removal steps limit the efficiency and practicality of reactions that rely on their use. Inspired by developments in asymmetric organocatalysis, where reactions rely on reversible covalent interactions between an organic substrate and a chiral mediator, we have developed a transient‐directing‐group approach to reductive Heck hydroarylation of alkenyl benzaldehyde substrates that proceeds under mild conditions. Highly stereoselective migratory insertion is facilitated by in situ formation of an imine from catalytic amounts of a commercially available amino acid additive. Computational studies reveal an unusual mode of enantioinduction by the remote chiral center in the transient directing group.

Metal‐coordinating directing groups have seen extensive use in the field of transition‐metal‐catalyzed alkene functionalization; however, their waste‐generating installation and removal steps limit the efficiency and practicality of reactions that rely on their use. Inspired by developments in asymmetric organocatalysis, where reactions rely on reversible covalent interactions between an organic substrate and a chiral mediator, we have developed a transient‐directing‐group approach to reductive Heck hydroarylation of alkenyl benzaldehyde substrates that proceeds under mild conditions. Highly stereoselective migratory insertion is facilitated by in situ formation of an imine from catalytic amounts of a commercially available amino acid additive. Computational studies reveal an unusual mode of enantioinduction by the remote chiral center in the transient directing group.