| Summary: | Herein is described the first enantioselective intramolecular allylation of alkenylnickel nucleophiles. These reactions are initiated by the addition of an arylboronic acid across an alkyne, followed by cyclization of the resulting alkenylnickel species onto an allylic phosphate. The reversible E/Z isomerization of the alkenylnickel species is essential for the success of the reactions.
This process delivers chiral 1,4-diene-containing hetero- and carbocycles, previously inaccessible via established rhodium catalysis, with excellent levels of regio- and stereocontrol. This reaction further demonstrates the power of reversible alkenylnickel E/Z isomerization in providing products that would otherwise be inaccessible using syn-selective alkyne carbometallation processes.
Attempts to extend this reactivity to other classes of electrophilic traps are also described.
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