A mild, aerobic, catalytic process for obtaining nitriles directly from alcohols and aqueous ammonia is described. The reaction proceeds via a dehydrogenation cascade mediated by catalytic CuI, bpy, and TEMPO in the presence of O2. The substrate scope is broad including various functionalized aromatic and aliphatic alcohols. This protocol enabled the one-pot synthesis of various biaryl heterocycles directly from commercially available alcohols.
The trifluoromethylthio group (SCF3) is a highly privileged modifier for drug molecules. Direct CH trifluoromethylthiolation reactions are highly valuable synthetic tools for the late‐stage modification of drug candidates, which have so far been underexplored. We report a palladium‐catalyzed ortho‐selective mono‐trifluoromethylthiolation reaction of arenes. The reaction proceeds through a key ligand exchange pathway using readily available silver trifluoromethylthiolate (AgSCF3). Acetic acid was found to be crucial to minimize oxidative dimerization of the starting materials and to facilitate the “SCF3−” transfer. We expect this strategy to have broad applications in CH functionalization reactions using a stand‐alone oxidant and various anions.
A general palladium catalyzed acetoxylation of benzylic C-H bonds has been developed. Picolinamides serve as an excellent directing group for the C-H activation of benzylic methyls. A wide range of 2-amino benzyl alcohol analogues were synthesized in good yields. The products demonstrated broad synthetic utilities toward various benzo-fused heterocycles. Mechanistic studies revealed the key rate-limiting C-H insertion step, which could be affected by the substitution pattern of the parent arene.
The organocatalytic additions of ascorbic acid to various α,β-unsaturated aldehydes via tandem 1,4-conjugate addition/hemiacetalization/hemiketalization were developed, which provided a rapid entry into the 5-5-5 spirodilactone cores of a family of ascorbylated natural products. Based on the described chemistry, total syntheses of leucodrin, leudrin and the proposed structure of dilaspirolactone were achieved.
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