This review focuses on the application of glycol cleavage reactions in the synthesis and derivatization of complex natural products. Reagent classics as well as recent developments are discussed. 1 Introduction 2 Mechanistic Aspects 3 Reagents and Examples 3.1 Periodate and Hypervalent Iodine 3.1.1 Periodic Acid and Periodates 3.1.2 Periodate on Wet Silica Gel 3.1.3 Phenyliodine Diacetate 3.1.4 Other Iodine Reagents 3.2 Lead Tetraacetate 3.3 Chromium Reagents 3.3.1 Pyridinium Chlorochromate 3.3.2 Other Chromium Reagents 3.4 Ruthenium Reagents 3.4.1 Tetra-n-propylammonium Perruthenate 3.4.2 Other Ruthenium Reagents 3.5 Manganese Reagents 3.5.1 Manganese(III) Acetate 3.5.2 Manganese Dioxide 3.5.3 Other Manganese Reagents 3.6 Miscellaneous 4 Conclusion

The heronapyrroles A–C have first been isolated from a marine-derived Streptomyces sp. (CMB-0423) in 2010. Structurally, these natural products feature an unusual nitropyrrole system to which a partially oxidized farnesyl chain is attached. The varying degree of oxidation of the sesquiterpenyl subunit in heronapyrroles A–C provoked the hypothesis that there might exist other hitherto unidentified metabolites. On biosynthetic grounds a mono-tetrahydrofuran-diol named heronapyrrole D appeared a possible candidate. We here describe a short asymmetric synthesis of heronapyrrole D, its detection in cultivations of CMB-0423 and finally the evaluation of its antibacterial activity. We thus demonstrate that biosynthetic considerations and the joint effort of synthetic and natural product chemists can result in the identification of new members of a rare class of natural products.

A short (5 steps) and highly efficient (25% overall yield) synthesis of paracaseolide A is described. Crucial steps are an α-iodination of a butenolide, a Suzuki coupling and a thermal Diels–Alder reaction. In attempts at Lewis acid catalyzed [4 + 2]-cycloadditions a set of novel dimerization products of the proposed biosynthetic paracaseolide A precursor were produced.

The direct oxidative cyclization of 1,5-dienes is a valuable synthetic method for the (dia)stereoselective preparation of substituted tetrahydrofurans. Closely related reactions start from 5,6-dihydroxy or 5-hydroxyalkenes to generate similar products in a mechanistically analogous manner. After a brief overview on the history of this group of transformations and a survey on mechanistic and stereochemical aspects, this review article provides a summary on applications in natural product synthesis. Moreover, current limitations and future directions in this area of chemistry are discussed.