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submitted on 18.12.2019 and posted on 23.12.2019by Brandon L. Coles-Taylor, Maximilian S. McCallum, Andrés G. Muñoz, Brian Michel
carbopalladation reactions represent a powerful approach to generating multiple
new C–C bonds and substituted alkenes, however regioselectivity is often
challenging for intermolecular variants. By utilizing ynol ethers as polarized
alkynes we observe complete regiocontrol of migratory insertion with Pd–Ar
species. A Heck reaction was used to turn-over the catalytic cycle by
intercepting the vinyl-Pd adduct of carbopalladation with a pendant alkene.
When using o-iodo styrenes substrates
the resulting products are oligosubstituted 1-indenol ethers with defined
stereochemistry based on the initial alkene geometry. By blocking β-hydride
elimination we demonstrated C–H and C–C reductive elimination steps for catalyst
turnover. Herein we report the optimization of reaction conditions, scope, and
alternative termination steps.