Arylative Intramolecular Allylation of Ketones with 1,3-Enynes Enabled by Catalytic Alkenyl-to-Allyl 1,4-Rhodium(I) Migration

We describe the implementation of this strategy in arylative intramolecular allylations of ketones to give stereochemically complex fused bicycles with high diastereoselectivities

Benjamin M. Partridge; Michael Callingham; William Lewis; Hon Wai Lam

2017

Scholarcy highlights

  • Alkenyl-to-allyl 1,4-rhodium(I) migration enables the generation of nucleophilic allylrhodium(I) species by remote CÀH activation
  • Nucleophilic allylations are important reactions that could benefit from CÀH functionalization principles
  • A 3,5-disubstituted arylboron reagent was used to minimize 1,4-rhodium(I) migration onto the aryl group as described previously, as it is well-known that migration onto an aryl ring ortho to a substituent is unfavorable. Pinacol boronates were used because 3,5-disubstituted variants are accessed through iridium-catalyzed CÀH borylation
  • Consistent with models proposed in prior rhodiumcatalyzed nucleophilic allylations, we suggest that allylation occurs through cyclic six-membered transition states
  • The products can be obtained in high enantioselectivities using a chiral sulfur-alkene ligand
  • The key step of the reaction is the alkenyl-to-allyl 1,4-rhodium(I) migration, a new mode of reactivity which enables the generation of nucleophilic allylrhodium(I) species without prefunctionalization of the allylic position

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