A General Three-Component Nozaki-Hiyama-Kishi-Type Reaction Enabled by Delayed Radical-Polar Crossover.

Nozaki-Hiyama-Kishi (NHK) reactions offer a mild approach for the formation of alcohol motifs through radical-polar crossover-based pathways from various radical precursors. However, the application of multicomponent NHK-type reactions, which allow the formation of multiple bonds in a single step, has been largely restricted to bulky alkyl radical precursors, thus limiting their expanded utilization. Herein, we disclose a general three-component NHK-type reaction enabled by delayed radical-polar crossover, which efficiently tolerates a plethora of radical precursors that were previously unavailable. This method enables the modular assembly of versatile homoallylic alcohols from feedstock chemicals with excellent chemo-, regio-, diastereo-, and enantioselectivities in a single step. Experimental studies and density functional theory (DFT) calculations reveal that the kinetically favored formation of an allylchromium(III) species is paramount for enforcing the delayed radical-polar crossover over direct radical addition. Finally, straightforward transformations and applications of the homoallylic alcohol products were demonstrated, showcasing the synthetic utility of this method.