Photocatalytic Alkyl Radical Addition Tandem Oxidation of Alkenyl Borates.

Photocatalytic oxidation is a popular transformation way for organic synthesis and is widely applied in academia and industry. Herein, we report a blue light-induced alkylation-oxidation tandem reaction for the synthesis of diverse ketones by combining alkyl radical addition and oxidation of alkenyl borates. This reaction shows excellent functional group compatibility in acceptable yields, and diversity of radical precursors is applicable.

Nickel-Catalyzed Switchable Site-Selective Alkene Hydroalkylation by Temperature Regulation.

Regiodivergent alkene functionalization that produces either regioisomer starting from the same raw materials is desirable. Herein, we report a nickel-catalyzed switchable site-selective alkene hydroalkylation. The selection of reaction temperatures leads to protocols that provide regiodivergent hydroalkylated products starting from a single alkene substrate. This protocol allows the convenient synthesis of α- and ß-branched protected amines, both of which are important to the fields of pharmaceutical chemistry and biochemistry. In addition, enantioenriched ß-branched alkylamines can be accessed in a catalytic asymmetric variant. Preliminary mechanistic studies indicate that the formation of a more stable nickelacycle provides the driving force of migration. The thermodynamic and kinetic properties of different reduction elimination intermediates are responsible for the switchable site-selectivity.

Transition-metal-free decarboxylative thiolation of stable aliphatic carboxylates.

A transition-metal-free decarboxylative thiolation protocol is reported in which primary, secondary, tertiary (hetero)aryl acetates and α-CN substituted acetates undergo the decarboxylative thiolation smoothly, to deliver a variety of functionalized aryl alkyl sulfides in moderate to excellent yields. Aryl diselenides are also amenable substrates for construction of C-Se bonds under the simple and mild reaction conditions. Moreover, the protocol is successfully applied to the late-stage modification of pharmaceutical carboxylates with satisfactory chemoselectivity and functional-group compatibility.

Fitness traits and underlying genetic variation related to host plant specialization in the aphid Sitobion avenae.

Sitobion avenae (F.) is an important cereal pest worldwide that can survive on various plants in the Poaceae, but divergent selection on different host plants should promote the evolution of specialized genotypes or host races. In order to evaluate their resource use strategies, clones of S. avenae were collected from oat and barley. Host-transfer experiments for these clones were conducted in the laboratory to compare their fitness traits. Our results demonstrated that barley clones had significantly lower fecundity and tended to have longer developmental times when transferred from barley to oat. However, oat clones developed faster after they were transferred to barley. Clones from oat and barley had diverged to a certain extent in terms of fecundity and developmental time of the nymphs. The separation of barley clones and oat clones of S. avenae was also evident in a principal component analysis. Barley clones tended to have higher broad-sense heritabilities for fitness traits than oat clones, indicating the genetic basis of differentiation between them. Barley clones showed significantly higher extent of specialization compared to oat clones from two measures of specialization (i.e., Xsp and Ysp). Therefore, barley clones were specialized to a certain extent, but oat clones appeared to be generalized. The fitness of S. avenae clones tended to increase with higher extent of specialization. The evolution toward ecological specialization in S. avenae clones, as well as the underlying genetic basis, was discussed.