Thio-based photosensitizer: a general strategy for preparing visible/NIR light absorbing heavy-atom-free photosensitizers was developed by performing a simple sulfur-for-oxygen atom substitution within existing fluorescent molecules.

Carbon-nitrogen bond formation from inert C-H bonds is an ideal organic transformation and a highly desirable method for the synthesis of N-containing molecules due to its high efficiency and atom economy. In this report, we develop a general reaction to achieve an unprecedented selective intramolecular amination of unactivated C-H bond in the absence of complex directing groups. Functionalized heterocyclic products are built up from readily available linear amines through simple and reliable silver catalysis, representing a new silver-based C-H functionalization. This method displays preference for primary sp 3 C-H bonds and exhibits distinct chemo-and regioselectivity compared to existing methods of direct amination (Hofmann-Löffler-Freytag reaction and nitrene insertion). The study highlights the manipulation of unfunctionalized groups in organic molecules to furnish complex structural units in the natural and bioactive molecules.

The development of visible‐light‐mediated allylation of unactivated sp3 C−H bonds is reported. The remote allylation was directed by the amidyl radical, which was generated by photocatalytic fragmentation of a pre‐functionalized amide precursor. Both aromatic and aliphatic amide derivatives could successfully deliver the remote C−H allylation products in good yields. A variety of electron deficient allyl sulfone systems could be used as δ‐carbon radical acceptor.

No abstract

While most organisms utilize 20 canonical amino acid building blocks for protein synthesis, adding additional candidates to the amino acid repertoire can greatly facilitate the investigation and manipulation of protein structures and functions. In this study, we report the generation of completely autonomous organisms with a 21 st ncAA, 5-hydroxytryptophan (5HTP). Like 20 canonical amino acids, 5-hydroxytryptophan can be biosynthesized in vivo from simple carbon sources and is subsequently incorporated into proteins in response to the amber stop codon. Using this unnatural organism, we have prepared a single-chain immunoglobulin variable fragment conjugated with a fluorophore and demonstrated the utility of these autonomous cells to monitor oxidative stress. Creation of this and other cells containing the 21 st amino acid will provide an opportunity to generate proteins and organisms with novel activities, as well as to determine the evolutionary consequences of using additional amino acid buildings.