Access to Substituted Indenol Ethers via a Regioselective Intermolecular Carbopalladation Cascade.

Alkyne carbopalladation reactions can rapidly generate multiple new C-C bonds; however, regioselectivity is challenging for intermolecular variants. Using ynol ethers, we observe complete regiocontrol of migratory insertion followed by a second migratory insertion with a pendant alkene to turn-over the catalytic cycle. The resulting products are oligosubstituted 1-indenol ethers with defined stereochemistry based on the initial alkene geometry. Blocking ß-hydride elimination allowed for C-H and C-C reductive elimination steps for catalyst turnover.

Accessing 4-oxy-substituted isoquinolinones via C-H activation and regioselective migratory insertion with electronically biased ynol ethers.

The rhodium-catalyzed C-H activation and annulation with ynol ethers to directly provide 4-oxy substituted isoquinolinones is reported. The polarized nature of ynol ethers provides an electronic bias for controlling the regioselectivity of the migratory insertion process. While the highly reactive nature of ynol ethers presents a challenge, mild conditions were found to provide product in moderate to good yield. Utility was demonstrated by application in the synthesis of a prolyl-4-hydroxylase inhibitor framework.