• Radical hydroxymethylation of alkyl iodides using formaldehyde as a C1 synthon.

      Caiger, Lewis; orcid: 0000-0001-5156-9684; Sinton, Conar; orcid: 0000-0002-5588-7548; Constantin, Timothée; orcid: 0000-0001-5376-1557; Douglas, James J; Sheikh, Nadeem S; Juliá, Fabio; orcid: 0000-0001-8903-4482; Leonori, Daniele; orcid: 0000-0002-7692-4504 (2021-07-06)
      Radical hydroxymethylation using formaldehyde as a C1 synthon is challenging due to the reversible and endothermic nature of the addition process. Here we report a strategy that couples alkyl iodide building blocks with formaldehyde through the use of photocatalysis and a phosphine additive. Halogen-atom transfer (XAT) from α-aminoalkyl radicals is leveraged to convert the iodide into the corresponding open-shell species, while its following addition to formaldehyde is rendered irreversible by trapping the transient O-radical with PPh . This event delivers a phosphoranyl radical that re-generates the alkyl radical and provides the hydroxymethylated product. [Abstract copyright: This journal is © The Royal Society of Chemistry.]
    • Radical hydroxymethylation of alkyl iodides using formaldehyde as a C1 synthon.

      Caiger, Lewis; orcid: 0000-0001-5156-9684; Sinton, Conar; orcid: 0000-0002-5588-7548; Constantin, Timothée; orcid: 0000-0001-5376-1557; Douglas, James J; Sheikh, Nadeem S; Juliá, Fabio; orcid: 0000-0001-8903-4482; Leonori, Daniele; orcid: 0000-0002-7692-4504 (2021-07-06)
      Radical hydroxymethylation using formaldehyde as a C1 synthon is challenging due to the reversible and endothermic nature of the addition process. Here we report a strategy that couples alkyl iodide building blocks with formaldehyde through the use of photocatalysis and a phosphine additive. Halogen-atom transfer (XAT) from α-aminoalkyl radicals is leveraged to convert the iodide into the corresponding open-shell species, while its following addition to formaldehyde is rendered irreversible by trapping the transient O-radical with PPh<sub>3</sub>. This event delivers a phosphoranyl radical that re-generates the alkyl radical and provides the hydroxymethylated product.
    • Structural basis of terephthalate recognition by solute binding protein TphC

      Gautom, Trishnamoni; orcid: 0000-0001-7602-1228; Dheeman, Dharmendra; orcid: 0000-0002-8933-954X; Levy, Colin; Butterfield, Thomas; Alvarez Gonzalez, Guadalupe; orcid: 0000-0003-4387-2231; Le Roy, Philip; orcid: 0000-0002-5496-0272; Caiger, Lewis; orcid: 0000-0001-5156-9684; Fisher, Karl; orcid: 0000-0003-3539-8939; Johannissen, Linus; orcid: 0000-0002-0916-9094; Dixon, Neil; orcid: 0000-0001-9065-6764; email: neil.dixon@manchester.ac.uk (Nature Publishing Group UK, 2021-10-29)
      Abstract: Biological degradation of Polyethylene terephthalate (PET) plastic and assimilation of the corresponding monomers ethylene glycol and terephthalate (TPA) into central metabolism offers an attractive route for bio-based molecular recycling and bioremediation applications. A key step is the cellular uptake of the non-permeable TPA into bacterial cells which has been shown to be dependent upon the presence of the key tphC gene. However, little is known from a biochemical and structural perspective about the encoded solute binding protein, TphC. Here, we report the biochemical and structural characterisation of TphC in both open and TPA-bound closed conformations. This analysis demonstrates the narrow ligand specificity of TphC towards aromatic para-substituted dicarboxylates, such as TPA and closely related analogues. Further phylogenetic and genomic context analysis of the tph genes reveals homologous operons as a genetic resource for future biotechnological and metabolic engineering efforts towards circular plastic bio-economy solutions.