Ni-catalysed regioselective 1,2-diarylation of unactivated olefins by stabilizing Heck intermediates as pyridylsilyl-coordinated transient metallacyclesElectronic supplementary information (ESI) available: Experimental procedures and characterization, and the 1H and 13C NMR spectra of new compounds. See DOI: 10.1039/c7sc04351a

We report a Ni-catalysed diarylation of unactivated olefins in dimethylpyridylvinylsilane by intercepting Heck C(sp 3 )-NiX intermediates, derived from aryl halides, with arylzinc reagents. This approach utilizes a modifiable pyridylsilyl moiety as a coordinating group that plays a dual role of intercepting oxidative addition species to promote Heck carbometallation, and stabilizing the Heck C(sp 3 )-NiX intermediates as transient metallacycles to suppress β-hydride elimination, and facilitate transmetalation/reductive elimination. This method affords 1,2-diarylethylsilanes, which can be readily oxidized to 1,2-diarylethanols that occur as structural motifs in 3-aryl-3,4-dihydroisocoumarin and dihydrostilbenoid natural products. Ni-catalysed diarylation of vinylpyridylsilanes with arylzinc reagents and aryl halides is reported by stabilizing Heck intermediates as pyridylsilyl-coordinated transient metallacycles.