In the context of solar‐to‐chemical energy conversion, inspired by natural photosynthesis, the synthesis, electrochemical properties and photoinduced electron‐transfer processes of three novel zinc(II)‐gold(III) bis(porphyrin) dyads [ZnII(P)–AuIII(P)]+ are presented (P: tetraaryl porphyrin). Time‐resolved spectroscopic studies indicated ultrafast dynamics (kET1
>1010 s−1) after visible‐light excitation, which finally yielded a charge‐shifted state [ZnII(P⋅+)–AuII(P)]+ featuring a gold(II) center. The lifetime of this excited state is quite long due to a comparably slow charge recombination (kBET2
≈3×108 s−1). The [ZnII(P⋅+)–AuII(P)]+ charge‐shifted state is reductively quenched by amines in bimolecular reactions, yielding the neutral zinc(II)–gold(II) bis(porphyrin) ZnII(P)–AuII(P). The electronic nature of this key gold(II) intermediate, prepared by chemical or photochemical reduction, is elucidated by UV/Vis, X‐band EPR, gold L3‐edge X‐ray absorption near edge structure (XANES) and paramagnetic 1H NMR spectroscopy as well as by quantum chemical calculations. Finally, the gold(II) site in ZnII(P)–AuII(P) is thermodynamically and kinetically competent to reduce an aryl azide to the corresponding aryl amine, paving the way to catalytic applications of gold(III) porphyrins in photoredox catalysis involving the gold(III/II) redox couple.
Amaryllidaceae alkaloids appeal to organic chemists with their attractive structures and their impressive antitumor and acetylcholinesterase inhibitory properties. We demonstrate a highly versatile access to this family of natural products. A general protocol with high yields in a sustainable electro-organic key transformation on a metal-free anode to spirodienones facilitates functionalization to the alkaloids.
Carbohydrates such as glucose are an abundant renewable resource that can be employed in synthetic processes as a source of carbon and/or hydrogen to yield products of high economical and biological impact. Herein, we report a versatile and environmentally friendly protocol for the one‐pot synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones, a privileged scaffold in medicinal chemistry, based on the use of glucose as an eco‐friendly reductant in alkaline aqueous medium. This method can be viewed as a blueprint for the development of further one‐pot sequences involving glucose as a reductant.
The electrochemical coupling of amines and carboxylic acids generates a wide variety of amides and dipeptides. The operationally simple and robust process is mediated by iodide and produces triphenylphosphine oxide as a recyclable co‐product. A combination of boron‐doped diamond (BDD) anode and a platinum cathode ensures maximum performance. More information can be found in the Research Article by T. Opatz et al. (DOI: 10.1002/chem.202201768). Artwork by L.M.G. based on an idea by T.O.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.