We report the results of a structured expert elicitation to identify the most likely types of potential food system disruption scenarios for the UK, focusing on routes to civil unrest. We take a ...backcasting approach by defining as an end-point a societal event in which 1 in 2000 people have been injured in the UK, which 40% of experts rated as “Possible (20–50%)”, “More likely than not (50–80%)” or “Very likely (>80%)” over the coming decade. Over a timeframe of 50 years, this increased to 80% of experts. The experts considered two food system scenarios and ranked their plausibility of contributing to the given societal scenario. For a timescale of 10 years, the majority identified a food distribution problem as the most likely. Over a timescale of 50 years, the experts were more evenly split between the two scenarios, but over half thought the most likely route to civil unrest would be a lack of total food in the UK. However, the experts stressed that the various causes of food system disruption are interconnected and can create cascading risks, highlighting the importance of a systems approach. We encourage food system stakeholders to use these results in their risk planning and recommend future work to support prevention, preparedness, response and recovery planning.
A short synthesis of the non-adjacent bis-THF core of the Annonaceous acetogenin cis-sylvaticin (1) is described. C(2) Symmetrical (Z,E,E,Z)- and (E,E,E,E)-tetraenes and were synthesised in six and ...three steps respectively from (1E,5E,9E)-cyclododeca-1,5,9-triene. Subsequent permanganate promoted asymmetric bi-directional oxidative cyclisation of tetraene was used to create the non-adjacent bis-THF core of 1, installing seven of the nine stereogenic centres present in the natural product in a single step. Desymmetrization of the oxidative cyclisation product by mono-tosylation gave access to a C11-C32 fragment of cis-sylvaticin.
Enantiomerically enriched 1,2‐diols can be prepared, in good enantiomeric excesses, by using a novel asymmetric dihydroxylation of enones with permanganate under phase‐transfer conditions (see ...scheme: e.g. R1=nBu, R2=(p‐OMe)C6H4).
The central non-adjacent bis-THF core of the Annonaceous acetogenin cis-sylvaticin has been established via the permanganate promoted asymmetric bi-directional oxidative cyclisation of a tetraene. ...The tetraene was obtained in five facile steps from commercially available triene 4.27 in good overall yield. Permanganate promoted asymmetric bi-directional oxidative cyclisation inserted the eight new stereogenic centres in good d.r.., thus providing rapid access to this advanced intermediate. Elaboration of the bis-THF core is described, illustrating the possibility of both a linear and bi-directional approach to cis-sylvaticin. An approach to the butenolide portion of cis-sylvaticin is also described. The key step involved asymmetric alkynyl addition to butenolide-aldehyde 3.6 and proceeded with good levels of diastereoselectivity. The permanganate-mediated asymmetric dihydroxylation of enones has been demonstrated in the presence of a chiral quaternary ammonium salt. Dihydroxylation of a variety of enone substrates produced the corresponding diols with good levels of enantioselectivity (50-80% ee). The reaction is clean and fast, producing the corresponding benzoic acid as the main by-product.
1,2‐Diole durch asymmetrische Phasentransferkatalyse: Durch eine neue, asymmetrische Dihydroxylierung von Enonen mit Permanganat unter Phasentransferbedingungen sind 1,2‐Diole mit hohen ...Enantiomerenüberschüssen zugänglich (siehe Schema: z. B. R1=nBu, R2=(p‐OMe)C6H4).
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