Mechanically Induced Sequential One-Pot Wittig Olefination–Diels-Alder Reaction: A Solvent-Free Approach to Complex Bicyclic Scaffolds

Analytical Data and Compound Numbering (numbering in publication vs. ELN entry) for the Publication entitled: "Mechanically Induced Sequential One-Pot Wittig Olefination–Diels-Alder Reaction: A Solvent-Free Approach to Complex Bicyclic Scaffolds"

The paper was published on 2025-08-26 in RSC Meachnochemistry.

RSC Mechanochem. 2025, DOI: 10.1039/D5MR00087D.

Authors: Nina Biedermann and Michael Schnürch

Context and methodology

Herein we present a mechanically induced, solvent-free protocol that sequentially combines the Wittig olefination and Diels-Alder cycloaddition in one-pot and enables the synthesis of structurally complex bicyclic compounds. This method proceeds entirely under ball milling conditions without the requirement of any solvent while eliminating the need for intermediate purification. Careful optimization of the milling parameters and reagent addition enables efficient conversion of various α,β-unsaturated aldehydes and ketones with electron-deficient dienophiles to the corresponding cycloadducts via diene intermediates, demonstrating high stereoselectivity and yielding exclusively endo Diels-Alder adducts. Furthermore, the extension of the sequence by a solvent-free one-pot oxidation is exemplified, achieving a three-step synthesis in a single milling vessel without intermediate workup and purification, which exhibits excellent green metrics in comparison with solution-based methods. This operationally simple and sustainable approach demonstrates the potential of mechanochemistry to streamline multistep organic synthesis, while reducing solvent use and energy demand.

The publication and its Supplementary Information can be found as open-access files on the publisher's website (see DOI).

All files containing the analytical raw data for all compounds given in the Supplementary Information of the manuscript are uploaded. An additional file named RSC_Mechanochem_2025-compound_list.pdf is uploaded, that should clearly link the compound number given in the paper to the respective entry in the ELN (nbiederm) and the respective analytical data file.

Technical details

The files uploaded contain the FIDs of NMR spectra recorded by an in-house Bruker Spectrometer. Standard software (such as MestreNova or Topspin) is required to display NMR spectra.