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The reactivity of the sulfonyl group varies dramatically from nucleophilic sulfinates through chemically robust sulfones to electrophilic sulfonyl halides—a feature that has been used extensively in medicinal chemistry, synthesis, and materials science, especially as bioisosteric replacements and structural analogs of carboxylic acids and other carbonyls. Despite the great synthetic potential of the carboxylic to sulfonyl functional group interconversions, a method that can convert carboxylic acids directly to sulfones, sulfinates and sulfonyl halides has remained out of reach. We report herein the development of a photocatalytic system that for the first time enables direct decarboxylative conversion of carboxylic acids to sulfones and sulfinates, as well as sulfonyl chlorides and fluorides in one step and in a multicomponent fashion. A mechanistic study prompted by the development of the new method revealed the key structural features of the acridine photocatalysts that facilitate the decarboxylative transformations and provided an informative and predictive multivariate linear regression model that quantitatively relates the structural features with the photocatalytic activity. 

This paper presents two case studies of the repurposing projects of decommissioned wind turbine blades in architectural and structural engineering applications conducted under a multinational research project is entitled “Re-Wind” (www.re-wind.info) that was funded by the US-Ireland Tripartite program. The group has worked closely together in the Re-Wind Network over the past five years to conduct research on the topic of repurposing of decommissioned FRP wind turbine blades. Repurposing is defined by the ReWind team as the reverse engineering, redesigning and remanufacturing of a wind blade that has reached the end of its life on a turbine and taken out of service and then reused as a load-bearing structural element in a new structure (e.g., bridge, transmission pole, sound barrier, sea-wall, shelter). Further repurposing examples are provided in a publicly available Re-Wind Design Catalog. The Re-Wind Network was the first group to develop practical methods and design procedures to make these new “second-life” structures. The Network has developed design and construction details for two full-size prototype demonstration structures – a pedestrian bridge constructed in Cork, Ireland in January 2022 and a transmission pole to be constructed at the Smoky Hills Wind Farm in Lincoln and Ellsworth Counties, in Kansas, USA in the late 2022. The paper provides details on the planning, design, analysis, testing and construction of these two demonstration projects. 

Direct installation of the sulfinate group by the functionalization of unreactive aliphatic C–H bonds can provide access to most classes of organosulfur compounds, because of the central position of sulfinates as sulfonyl group linchpins. Despite the importance of the sulfonyl group in synthesis, medicine, and materials science, a direct C(sp 3 )–H sulfination reaction that can convert abundant aliphatic C–H bonds to sulfinates has remained elusive, due to the reactivity of sulfinates that are incompatible with typical oxidation-driven C–H functionalization approaches. We report herein a photoinduced C(sp 3 )–H sulfination reaction that is mediated by sodium metabisulfite and enables access to a variety of sulfinates. The reaction proceeds with high chemoselectivity and moderate to good regioselectivity, affording only monosulfination products and can be used for a solvent-controlled regiodivergent distal C(sp 3 )–H functionalization. 

Hematopoietic stem cell transplantation (HSCT) can replace endogenous microglia with circulation-derived macrophages but has high mortality. To mitigate the risks of HSCT and expand the potential for microglia replacement, we engineered an inhibitor-resistant CSF1R that enables robust microglia replacement. A glycine to alanine substitution at position 795 of human CSF1R (G795A) confers resistance to multiple CSF1R inhibitors, including PLX3397 and PLX5622. Biochemical and cell-based assays show no discernable gain or loss of function. G795A- but not wildtype-CSF1R expressing macrophages efficiently engraft the brain of PLX3397-treated mice and persist after cessation of inhibitor treatment. To gauge translational potential, we CRISPR engineered human-induced pluripotent stem cell–derived microglia (iMG) to express G795A. Xenotransplantation studies demonstrate that G795A-iMG exhibit nearly identical gene expression to wildtype iMG, respond to inflammatory stimuli, and progressively expand in the presence of PLX3397, replacing endogenous microglia to fully occupy the brain. In sum, we engineered a human CSF1R variant that enables nontoxic, cell type, and tissue-specific replacement of microglia.