The effect of neighborhood density on visual word recognition was found to be facilitatory for words but inhibitory for nonwords in 3 lexical-decision experiments. However, the facilitation virtually disappeared when the task was changed to semantic categorization (animal vs. nonanimal), despite the presence of a strong frequency effect. None of these experiments showed a consistent inhibitory effect of a higher frequency neighbor. The absence of inhibitory effects suggests that competition does not play a key role in visual word recognition. The data also suggest that the neighborhood density effect is not an access effect but is a task-dependent effect instead.

The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process.

No abstract

Axially chiral biaryl scaffolds are essential structural units in chemistry. The asymmetric Pd-catalyzed Suzuki–Miyaura cross-coupling reaction has been widely recognized as one of the most practical methods for constructing atropisomers of biaryls. However, longstanding challenges remain in this field. For example, substrate scope is often narrow and specialized, functional groups and heterocycles can lead to reduced reactivity and selectivity, bulky ortho-substituents are usually needed, and reported methods are generally inapplicable to tetra-ortho-substituted biaryls. We have developed an unprecedented highly enantioselective N-heterocyclic carbene (NHC)-Pd catalyzed Suzuki–Miyaura cross-coupling reaction for the synthesis of atropisomeric biaryls. These reactions enable efficient coupling of aryl halides (Br, Cl) or aryl triflates with various types of aryl boron compounds (B­(OH)2, Bpin, Bneo, BF3K), tolerate a remarkably broad scope of functional groups and heterocycles (>41 examples), employ low loading of catalyst (0.2–2 mol %), and proceed under mild conditions. The protocol provided general and efficient access to various atropisomeric biaryls and heterobiaryls in excellent enantioselectivities (up to 99% ee) with no need of using bulky ortho-substituted substrates and was effective for the synthesis of tetra-ortho-substituent biaryls. Moreover, the method was successfully applied to the diastereo- and enantioselective synthesis of atropisomeric ternaphthalenes. Critical to the success of the reaction is the development and application of an extremely bulky C 2-symmetric chiral NHC, (R,R,R,R)-DTB-SIPE, as the ligand for palladium. To the best of our knowledge, this is the first highly enantioselective (>90% ee) example of a chiral NHC-metal-catalyzed C­(sp2)–C­(sp2) cross-coupling reaction.

Microneedles with insulin-loaded glucose-responsive particles are promising to control the blood glucose levels of diabetic patients.