Science of Synthesis

Pineschi, M.; Boldrini, C., Science of Synthesis: Advances in Organoboron Chemistry towards Organic Synthesis, (2019) 1, 183.

Functionalized allylic boron compounds are important reagents in synthetic organic chemistry. In 2008, Oshima and co-workers reported nickel-catalyzed ring-opening reactions of vinylcyclopropanes with bis(pinacolato)diboron (‌2‌) to provide a novel entry to functionalized allylic boron compounds. Using bis(η4-cycloocta-1,5-diene)nickel(0) as a catalyst in the presence of tricyclopentylphosphine and tribasic potassium phosphate trihydrate in toluene/methanol, electron-poor vinylcyclopropanes of type ‌1‌ undergo the ring-opening reaction with bis(pinacolato)diboron (‌2‌), yielding allylic boronates ‌3‌ with high E selectivity through an SN2′ mechanism (‌Scheme 1‌).[‌1‌]

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References