Enantioselective Allylation from Allene, a Petroleum Cracking Byproduct
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Allene (C3H4) gas is produced and separated on million-metric-ton scale per year during petroleum refining but is only rarely employed in chemical manufacturing. Meanwhile, the addition of an allyl group (C3H5) to ketone-containing molecules is among the most common
and prototypical reactions in organic synthesis. Herein, we report that the combination of allene with environmentally benign hydrosilanes can replace harsher, more wasteful, and more
expensive allylmetal reagents in enantioselective ketone allylation reactions. This process is catalyzed by an earth-abundant metal and commercially available ligands, operates without specialized equipment or pressurization, and tolerates a broad range of functional groups. Furthermore, the exceptional chemoselectivity of our catalyst system enables industrially relevant C3 hydrocarbon mixtures of allene with methylacetylene and propylene to be applied
directly. Based on our strategy, we anticipate the rapid development of methods that leverage this unexploited feedstock as a surrogate for existing nucleophilic allylation reagents.