Pd-catalyzed C-H functionalizations promoted by transient directing groups remain largely limited to C-H arylation only. Herein, we report a diverse set of ortho-C(sp)-H functionalizations of benzaldehyde substrates using the transient directing group strategy. Without installing any auxiliary directing group, Pd(II)-catalyzed C-H arylation, chlorination, bromination, and Ir(III)-catalyzed amidation, could be achieved on benzaldehyde substrates. The transient directing groups formed in situ via imine linkage can override other coordinating functional groups capable of directing C-H activation or catalyst poisoning, significantly expanding the scope for metal-catalyzed C-H functionalization of benzaldehydes. The utility of this approach is demonstrated through multiple applications, including late-stage diversification of a drug analogue.
A novel strategy for asymmetric Shono‐type oxidative cross‐coupling has been developed by merging copper catalysis and electrochemistry, affording C1‐alkynylated tetrahydroisoquinolines with good to excellent enantioselectivity. The use of TEMPO as a co‐catalytic redox mediator is crucial not only for oxidizing a tetrahydroisoquinoline to an iminium ion species but also for decreasing the oxidation potential of the reaction. A novel bisoxazoline ligand is also reported.
In this work, an efficient synthetic route was developed to construct PAHs with diverse shape, width, and edge topology. The precursors of PAHs were obtained by using a direct arylation of arenes via a transient ligand-directed C−H functionalization strategy and the cycloaromatization was readily achieved by using a Brønsted acid catalyst. This novel route provides an opportunity to build up PAHs in a highly efficient manner.
A novel strategy for the N‐arylation of NH‐sulfoximines has been developed by merging nickel catalysis and electrochemistry (in an undivided cell), thereby providing a practical method for the construction of sulfoximine derivatives. Paired electrolysis is employed in this protocol, so a sacrificial anode is not required. Owing to the mild reaction conditions, excellent functional group tolerance and yield are achieved. A preliminary mechanistic study indicates that the anodic oxidation of a NiII species is crucial to promote the reductive elimination of a C−N bond from the resulting NiIII species at room temperature.
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