Persistent free radicals have become indispensable in the synthesis of organic materials by living radical polymerization. However, examples of their use in the synthesis of small molecules are rare. Herein, we report the application of persistent radical and quinone methide intermediates to the synthesis of the resveratrol tetramers nepalensinol B and vateriaphenol C. The spontaneous cleavage and reconstitution of exceptionally weak carbon-carbon bonds has enabled a stereoconvergent oxidative dimerization of racemic materials in a transformation that likely coincides with the biogenesis of these natural products. The efficient synthesis of higher-order oligomers of resveratrol will facilitate the biological studies necessary to elucidate their mechanism(s) of action.

The total synthesis of lundurines A–C has been accomplished in racemic and enantiopure forms in 11–13 and 12–14 steps, respectively, without protection/deprotection of functional groups, by a novel tandem double condensation/Claisen rearrangement, a gold(I)-catalyzed alkyne hydroarylation, a cyclopropanation via formal [3 + 2] cycloaddition/nitrogen extrusion, and a remarkable olefin migration through a vinylcyclopropane retro-ene/ene reaction that streamlines the endgame.

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The intermolecular gold(I)-catalyzed reaction between arylalkynes and alkenes leads to cyclobutenes by a [2 + 2] cycloaddition, which takes place stepwise, first by formation of cyclopropyl gold(I) carbenes, followed by a ring expansion. However, 1,3-butadienes are also formed in the case of ortho-substituted arylalkynes by a metathesis-type process. The corresponding reaction of alkenes with aryl-1,3-butadiynes, ethynylogous to arylalkynes, leads exclusively to cyclobutenes. A comprehensive mechanism for the gold(I)-catalyzed reaction of alkynes with alkenes is proposed on the basis of density functional theory calculations, which shows that the two pathways leading to cyclobutenes or dienes are very close in energy. The key intermediates are cyclopropyl gold(I) carbenes, which have been independently generated by retro-Buchner reaction from stereodefined 1a,7b-dihydro-1H-cyclopropa[a]naphthalenes.

Chiral gold­(I) catalysts have been designed based on a modified JohnPhos ligand with a distal C 2-2,5-diarylpyrrolidine that creates a tight binding cavity. The C 2-chiral element is close to where the C–C bond formation takes place in cyclizations of 1,6-enynes. These chiral mononuclear catalysts have been applied for the enantioselective 5-exo-dig and 6-endo-dig cyclization of different 1,6-enynes as well as in the first enantioselective total synthesis of three members of the carexane family of natural products. Opposite enantioselectivities have been achieved in seemingly analogous reactions of 1,6-enynes, which result from different chiral folding of the substrates based on attractive aryl–aryl interactions.

This Data Descriptor announces the submission to public repositories of the monoterpene indole alkaloid database (MIADB), a cumulative collection of 172 tandem mass spectrometry (MS/MS) spectra from multiple research projects conducted in eight natural product chemistry laboratories since the 1960s. All data have been annotated and organized to promote reuse by the community. Being a unique collection of these complex natural products, these data can be used to guide the dereplication and targeting of new related monoterpene indole alkaloids within complex mixtures when applying computer-based approaches, such as molecular networking. Each spectrum has its own accession number from CCMSLIB00004679916 to CCMSLIB00004680087 on the GNPS. The MIADB is available for download from MetaboLights under the identifier: MTBLS142 ( https://www.ebi.ac.uk/metabolights/MTBLS142 ).

The total synthesis of seven members of the lapidilectine and grandilodine family of alkaloids has been accomplished in racemic and enantiopure form without protection/deprotection of functional groups. The two key steps, an 8-endo-dig hydroarylation and a 6-exo-trig photoredox cyclization, were catalyzed using gold. A rationale for the formation of the cyclopropane ring of the lundurines is also provided.

The first total synthesis of cannabimovone from Cannabis sativa and anhydrocannabimovone was achieved by means of a highly stereoselective gold(I)‐catalyzed cycloisomerization. The results led to reassignment of the structure of anhydrocannabimovone.