C-centered radical cyclization under electrochemical conditions is a feasible strategy for constructing cyclic structures. Reported herein is the electrochemical synthesis of highly functionalized 1-naphthols using alkynes and 1,3-dicarbonyl compounds by (4 + 2) annulation of C-centered radical. Electrolysis was conducted with Cp2Fe as redox catalyst, thereby eliminating the use of oxidants and transition-metal catalysts. The synthesized 1-naphthol compounds showed good antitumor activity in vitro, and further studies indicated that compound 3bl induced tumor cell apoptosis.

The direct conversion of unactivated alkanes and cycloalkanes into structurally diverse molecules through aliphatic C-H functionalization is a useful process, which has attracted intense interest from academia and industry. Methods to control chemo-and site-selectivity, combined with asymmetric catalysis, provide appealing access to high value-added enantiomer-enriched compounds but are far less developed. This review focuses on recent progress in (i) asymmetric reactions of alkanes or cycloalkanes with prochiral substrates which generate a stereocenter adjacent to the cleaved C(sp 3 )-H bond, and (ii) C(sp 3 )-H enantiodiscriminatory reactions creating a new stereogenic center on the carbon of a cleaved C(sp 3 )-H bond. Elegant strategies are discussed, including (a) metal carbene-induced C-H insertions by chiral rhodium catalysts, (b) metal-oxo-mediated C-H oxidation by biomimetic manganese catalysts, (c) enzyme catalysis by cytochromes P450 variants, and (d) dual catalysis by a photocatalyst and a chiral Lewis acid (CLA) or a chiral phosphoric acid (CPA). These catalytic systems can not only precisely recognize primary, secondary and tertiary C-H bonds at specific positions in alkanes and cycloalkanes, but also support a high level of stereoselectivity in the reactions. It is expected that the advances will stimulate further progress in asymmetric catalysis, synthetic methodology, pharmaceutical development and industrial processes.

We have developed a metal- and oxidant-free method for the synthesis of rutaecarpine alkaloids via an electrochemical CDC reaction.

Peptides have been promising molecular scaffolds for the development of potential therapeutics with high affinity and specificity to biomacromolecules. However, their inherent proteolytic instability significantly hampers their biological applications. Strategies that can stabilize peptides against proteolytic digestion on the basis of noncovalent interactions-without extensive manipulation of the sequence or use of unnatural residues-are greatly desired. In this work, we developed a general, convenient, and efficient strategy for the stabilization of peptides against proteolysis, which involves noncovalent π-π interactions between aromatic amino acid residues in peptides and synthetic electron-deficient aromatics (NDI), together with the implication of steric hindrance (from the bulky NDI moiety), and the enhancement of peptide α-helicity. This strategy is complementary in concept to the conventional well-established covalent approaches for peptide stabilization, and is thus promising for being utilized, in combination with the latter ones, to circumvent the problem of proteolytic instability of peptides. We envisioned that this study should provide invaluable guidelines to the design and synthesis of organic molecule-peptide hybrids with significantly improved proteolytic resistance, and benefit the development of peptide therapeutics and probes.

Direct and selective C−H methylation is a powerful tool with which to install methyl groups into organic molecules, and is particularly useful in pharmaceutical chemistry. However, practical methods for such modification of biologically interesting targets have been rarely developed. We here report an iron‐catalyzed C(sp3)−H methylation reaction of glycine derivatives, peptides and drug‐like molecules in an alcohol in the presence of di‐tert‐butyl peroxide. A readily available iron catalyst plays multiple roles in the transformation, which accelerates oxidation of C−N bonds to C=N double bonds, activates imine intermediates as Lewis acids by bidentate chelation, and at the same time facilitates cleavage of the peroxide to generate methyl radicals. A variety of methylated N‐aryl glycine derivatives and peptides were obtained in good yield and with excellent chemo‐ and site‐selectivity. This reaction is scalable, easily managed, and can be completed within 1–2 h. It features an economic, bio‐friendly catalyst, a green solvent and low toxic reagents, and will provide effective access to precise C−H modification of biomolecules and natural products.