- Remote Functionalization of α,β-Unsaturated Carbonyls by Multimetallic Sequential Catalysis
Romano, C.; Fiorito, D.; Mazet, C.
J. Am. Chem. Soc. 2019, 141, 16983-16990
The remote functionalization of α,β-unsaturated carbonyls by an array of multimetallic sequential catalytic systems is described. The reactions are triggered by hydrometallation using [Pd–H] or [Ru–H] isomerization catalysts and driven by the formation of thermodynamically more stable 1,2-vinyl arenes. The Pd-catalyzed deconjugative isomerization was combined with a Cu-catalyzed β-borylation of the transiently generated styrenyl derivatives to deliver a range of products that would not be accessible with the use of a single catalyst. [Pd/Cu] catalytic systems were also identified for the highly enantioselective α-hydroboration and α-hydroamination of the styrenyl intermediates. Difunctionalization simultaneously at the benzylic and homobenzylic positions was achieved by combining the isomerization process with Sharpless asymmetric dihydroxylation (SAD) using [Pd/Os] or [Ru/Os] couples. Starting from a simple α,β-unsaturated ester, an isomerization/dihydroxylation/lactonization sequence gave access to a naturally occurring γ-butyrolactone in good yield, excellent diastereo- and enantioselectivity.
DOI : 10.1021/jacs.9b09373
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