Four to six percent of plants, distributed over different angiosperm families, entice pollinators by deception [1]. In these systems, chemical mimicry is often used as an efficient way to exploit the olfactory preferences of animals for the purpose of attracting them as pollinators [2,3]. Here, we report a very specific type of chemical mimicry of a food source. Ceropegia sandersonii (Apocynaceae), a deceptive South African plant with pitfall flowers, mimics attacked honeybees. We identified kleptoparasitic Desmometopa flies (Milichiidae) as the main pollinators of C. sandersonii. These flies are well known to feed on honeybees that are eaten by spiders, which we thus predicted as the model chemically mimicked by the plant. Indeed, we found that the floral scent of C. sandersonii is comparable to volatiles released from honeybees when under simulated attack. Moreover, many of these shared compounds elicited physiological responses in antennae of pollinating Desmometopa flies. A mixture of four compounds-geraniol, 2-heptanone, 2-nonanol, and (E)-2-octen-1-yl acetate-was highly attractive to the flies. We conclude that C. sandersonii is specialized on kleptoparasitic fly pollinators by deploying volatiles linked to the flies' food source, i.e., attacked and/or freshly killed honeybees. The blend of compounds emitted by C. sandersonii is unusual among flowering plants and lures kleptoparasitic flies into the trap flowers. This study describes a new example of how a plant can achieve pollination through chemical mimicry of the food sources of adult carnivorous animals.
A TiIII‐mediated radical cyclization cascade has been used for the synthesis of the sesquiterpenes (+)‐albicanol, (+)‐drimanol, and (+)‐drimanic acid. Starting from all‐trans‐farnesol, (+)‐albicanol could be prepared in seven steps in an overall yield of 14.9 %. Furthermore, a highly diastereoselective hydrogenation of (+)‐albicanol to give (+)‐drimanol has been developed. We used the synthesized (+)‐drimanic acid to achieve the first synthesis of the marine sesquiterpene hydroquinone deoxyspongiaquinol and the quinone deoxyspongiaquinone. Thus, this synthetic strategy gave access to five natural products.
New chemical probes have been designed to facilitate the identification of adenosine-to-inosine (A-to-I) edited RNAs. These reagents combine a conjugate acceptor for selective inosine covalent modification with functional groups for bioorthogonal biotinylation. The resulting biotinylated RNA was enriched and verified with RT-qPCR. This powerful chemical approach provides new opportunities to identify and quantify A-to-I editing sites.
The first asymmetric synthesis of the sesquiterpene quinones 3‐oxo‐ and 3β‐hydroxytauranin (1, 2) was achieved and the originally proposed structure of 3α‐hydroxytauranin was revised. The protected benzyl chloride 5 was obtained in six steps starting from 4‐bromo‐3,5‐dihydroxybenzoic acid (8) via a highly scalable approach. The troublesome Negishi coupling of the benzyl chloride 5 with alkenyldimethylalane 6 was optimized to furnish all‐trans‐farnesylarene 14 in very good yield. This prenylated arene was transformed in six additional steps to 3β‐hydroxytauranin (2). Finally, a new convenient access to propargylated terpenes without using dry cryogenic ammonia and gaseous allene or propyne is described.
The new piperideine alkaloid cicindeloine (3) was isolated from the pygidial glands of the beetles Stenus cicindeloides and Stenus solutus. The structure and absolute configuration of 3 were elucidated by NMR spectroscopy and asymmetric synthesis, respectively. A very efficient gram‐scale synthesis of 3 was developed using an intramolecular aza‐Wittig reaction as the final step. The synthetic route is comprised of 12 steps and proceeds in 20 % total yield. Nine of the 12 steps were conducted without column chromatography.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.