School of Chemistry, University of Bristol, E-mail: matt.crump@bristol.ac.uk; chris.wil † Electronic supplementary information procedures and characterisation data for and structural statistics for derivatised A DOI: 10.1039/c5sc03864b ‡ Current address: CAS Key Laboratory Systems, Wuhan Institute of Physics and of Sciences, Wuhan, Hubei Province 4300 § Current address: Fyeld Business & Res CM5 0GS, UK. Cite this: Chem. Sci., 2016, 7, 1779

Extended linear and cyclised polyketide mimics were synthesized and high-resolution solution NMR structures were used to probe the interactions of the actinorhodin polyketide ACP with these surrogates.

The tyrosine kinase A (TrkA) receptor is a validated therapeutic intervention point for a wide range of conditions. TrkA activation by nerve growth factor (NGF) binding the second extracellular immunoglobulin (TrkAIg2) domain triggers intracellular signaling cascades. In the periphery, this promotes the pain phenotype and, in the brain, cell survival or differentiation. Reproducible structural information and detailed validation of protein–ligand interactions aid drug discovery. However, the isolated TrkAIg2 domain crystallizes as a β-strand-swapped dimer in the absence of NGF, occluding the binding surface. Here we report the design and structural validation by nuclear magnetic resonance spectroscopy of the first stable, biologically active construct of the TrkAIg2 domain for binding site confirmation. Our structure closely mimics the wild-type fold of TrkAIg2 in complex with NGF (1WWW.pdb), and the 1H–15N correlation spectra confirm that both NGF and a competing small molecule interact at the known binding interface in solution.

An efficient strategy for the total synthesis of (-)-blepharocalyxin D and an analogue is described. The key step involves an acid-mediated cascade process in which reaction of methyl 3,3-dimethoxypropanoate with gamma,delta-unsaturated alcohols possessing diastereotopic styrenyl groups gives trans-fused bicyclic lactones with the creation of two rings and four stereocenters in one pot.

A versatile method for the synthesis of orthogonally protected D-xylose 1-thioethers is described using unusual silyl group migrations which were pivotal in the synthesis of 4,8-dimethyl-6-O-(2',4'-di-O-methyl-β-D-xylopyranosyl)hydroxyquinoline confirming the structure and absolute configuration of the natural product.

trans-2,8-Dioxabicyclodecanes were prepared in high yield with the creation of up to three stereocenters in a single pot by the acid-mediated reaction of γ,δ-unsaturated alcohols with aldehydes (see scheme, Bn=benzyl). This versatile reaction enables the stereoselective introduction of substituents at the C3, C4, C7, and C9 positions of the bicyclic framework.