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We report computationally-guided protein engineering of monomeric streptavidin Rh(iii) artificial metalloenzyme to enhance catalysis of the enantioselective coupling of acrylamide hydroxamate esters and styrenes. Increased TON correlates with calculated distances between the Rh(iii) metal and surrounding residues, underscoring an artificial metalloenzyme's propensity for additional control in metal-catalyzed transformations by through-space interactions.

Herein we disclose an iron-catalyzed method to access skeletal rearrangement reactions akin to the Dowd-Beckwith ring expansion from unactivated C(sp3)-H bonds. Photoinduced ligand-to-metal charge transfer at the iron center generates a chlorine radical, which abstracts electron-rich C(sp3)-H bonds. The resulting unstable alkyl radicals can undergo rearrangement in the presence of suitable functionality. Addition to an electron deficient olefin, recombination with a photoreduced iron complex, and subsequent protodemetallation allows for redox-neutral alkylation of the resulting radical. Simple adjustments to the reaction conditions enable the selective synthesis of the directly alkylated or the rearranged-alkylated products. As a radical clock, these rearrangements also enable the measurement of rate constants of addition into various electron deficient olefins in the Giese reaction.

This document explores the use of ligand-to-metal charge transfer (LMCT) catalysis with base metals, such as nickel, cobalt, and copper, in organic transformations. The authors discuss recent advancements in the field and the potential for expanding the synthetic repertoire of this strategy. They emphasize the importance of refining ligands to promote organometallic mechanisms and further developing photoinduced LMCT for sustainable synthetic methods. The document includes contributions from researchers Sean M. Treacy and Tomislav Rovis, who have made significant contributions to the field. [Extracted from the article]

This article presents a new experimental protocol for benchmarking the reactivity of chiral catalysts in asymmetric catalysis. The protocol involves comparing the performance of a benchmarking catalyst to that of a structurally dissimilar catalyst in a single competition experiment. The authors validated this approach using N-heterocyclic carbenes (NHCs) as organocatalysts and phosphoramidites as chiral ligands for transition-metal catalysis. The results demonstrate the usefulness of this protocol in understanding the relationship between catalyst structure and reactivity in asymmetric catalysis. The article also pays tribute to Keith Fagnou, a respected colleague. [Extracted from the article]

Recent advances in photoredox catalysis have made it possible to achieve various challenging synthetic transformations, polymerizations and surface modifications.sup.1-3. All of these reactions require ultraviolet- or visible-light stimuli; however, the use of visible-light irradiation has intrinsic challenges. For example, the penetration of visible light through most reaction media is very low, leading to problems in large-scale reactions. Moreover, reactants can compete with photocatalysts for the absorption of incident light, limiting the scope of the reactions. These problems can be overcome by the use of near-infrared light, which has a much higher penetration depth through various media, notably biological tissue.sup.4. Here we demonstrate various photoredox transformations under infrared radiation by utilizing the photophysical process of triplet fusion upconversion, a mechanism by which two low-energy photons are converted into a higher-energy photon. We show that this is a general strategy applicable to a wide range of photoredox reactions. We tune the upconversion components to adjust the output light, accessing both orange light and blue light from low-energy infrared light, by pairwise manipulation of the sensitizer and annihilator. We further demonstrate that the annihilator itself can be used as a photocatalyst, thus simplifying the reaction. This approach enables catalysis of high-energy transformations through several opaque barriers using low-energy infrared light.Photoredox transformations are achieved with infrared light by using triplet fusion upconversion that converts infrared into visible light, enabling the use of photoredox chemistry on larger scales and through barriers that are impenetrable by visible light., Author(s): Benjamin D. Ravetz [sup.1] , Andrew B. Pun [sup.1] , Emily M. Churchill [sup.1] , Daniel N. Congreve [sup.2] , Tomislav Rovis [sup.1] , Luis M. Campos [sup.1] Author [...]

Keywords: electrochemistry; electrocatalysis; olefin metathesis; ruthenium catalysis EN electrochemistry electrocatalysis olefin metathesis ruthenium catalysis 1477 1481 5 07/11/23 20230725 NES 230725 Graph Olefin metathesis is one of the most valuable reactions in organic chemistry for the formation of C=C bonds, as reflected by its widespread application in synthetic chemistry, [1] materials science, [2] and polymer science. Electrochemistry, electrocatalysis, olefin metathesis, ruthenium catalysis. [Extracted from the article]

Alkenes are the most ubiquitous prochiral functional groups--those that can be converted from achiral to chiral in a single step--that are accessible to synthetic chemists. For this reason, difunctionalization reactions [...]