Palladium-Catalyzed β-C(sp 3 )-H Arylation of Silyl Prop-1-en-1-ol Ethers with Aryl Halides: Entry to α,β -Unsaturated Ketones.

A palladium(0)-catalyzed β-C(sp 3 )-H arylation of silyl prop-1-en-1-ol ethers with aryl halides for the synthesis of α,β -unsaturated ketones is presented. In contrast to the reported β-C(sp 3 )-H arylation of ketones, the chemoselectivity of this current method relies on the Pd(0) catalytic systems and reaction temperatures: While using the Pd(dba) 2 /DavePhos/KF system at 80 °C resulted in β-C(sp 3 )-H monoarylation to produce β-monoarylated α,β -unsaturated ketones, harnessing the Pd(OAc) 2 / t -Bu XPhos/K 2 HPO 4 system at 110 °C induced β-C(sp 3 )-H diarylation to afford β,β -diarylated α,β -unsaturated ketones. The method provides a versatile route that uses readily available ketone-derivatized α-nonsubstituted silyl prop-1-en-1-ol ethers as the alkene sources and is characterized by a good functional group compatibility, a broad substrate scope, and an excellent selectivity.