Collagen model peptides (CMPs) serve as tools for understanding stability and function of the collagen triple helix and have a potential for biomedical applications. In the past, interstrand cross‐linking or conformational preconditioning of proline units through stereoelectronic effects have been utilized in the design of stabilized CMPs. To further study the effects determining collagen triple helix stability we investigated a series of CMPs containing synthetic diproline‐mimicking modules (ProMs), which were preorganized in a PPII‐helix‐type conformation by a functionalizable intrastrand C2 bridge. Results of CD‐based denaturation studies were correlated with calculated (DFT) conformational preferences of the ProM units, revealing that the relative helix stability is mainly governed by an interplay of main‐chain preorganization, ring‐flip preference, adaptability, and steric effects. Triple helix integrity was proven by crystal structure analysis and binding to HSP47.

A 12‐step total synthesis of the natural product dysiherbol A, a strongly anti‐inflammatory and anti‐tumor avarane meroterpene isolated from the marine sponge Dysidea sp., was elaborated. As key steps, the synthesis features an enantioselective Cu‐catalyzed 1,4‐addition/enolate‐trapping opening move, an Au‐catalyzed double cyclization to build up the tetracyclic core‐carbon skeleton, and a late installation of the C5‐bridgehead methyl group via proton‐induced cyclopropane opening associated with spontaneous cyclic ether formation. The obtained pentacyclic compound (corresponding to an anhydride of the originally suggested structure for dysiherbol A) showed identical spectroscopic data as the natural product, but an opposite molecular rotation. CD‐spectroscopic measurements finally confirmed that both the constitution and the absolute configuration of the originally proposed structure of (+)‐dysiherbol A need to be revised.

Herein we describe a straightforward approach for the scale-up of photoredox cross-coupling reactions from milligram to multigram scale using immersion-well batch reactors with minimal reoptimization of the reaction conditions. This approach can be applied to both homogeneous and, more significantly, heterogeneous reaction mixtures. Furthermore, we have used an immersion-well side-loop reactor to perform a reaction on a 400 mmol scale (86 g of aryl bromide).

Collagen model peptides (CMPs) serve as tools for understanding stability and function of the collagen triple helix and have a potential for biomedical applications. In the past, interstrand cross‐linking or conformational preconditioning of proline units through stereoelectronic effects have been utilized in the design of stabilized CMPs. To further study the effects determining collagen triple helix stability we investigated a series of CMPs containing synthetic diproline‐mimicking modules (ProMs), which were preorganized in a PPII‐helix‐type conformation by a functionalizable intrastrand C2 bridge. Results of CD‐based denaturation studies were correlated with calculated (DFT) conformational preferences of the ProM units, revealing that the relative helix stability is mainly governed by an interplay of main‐chain preorganization, ring‐flip preference, adaptability, and steric effects. Triple helix integrity was proven by crystal structure analysis and binding to HSP47.

We report here a concise and divergent enantioselective total synthesis of the revised structures of marine anti-cancer sesquiterpene hydroquinone meroterpenoids (+)-dysiherbols A–E (6–10) using dimethyl predysiherbol 14 as a key...