Fig. 7: Proposed catalytic cycle.
From: Nickel-catalyzed switchable 1,3-dienylation and enantioselective allenylation of phosphine oxides
Pathways are shown for the catalytically afforded reactive species from propargylic carbonate with nickel catalysts. Under basic condition, the phosphine L23-bound allenylnickel intermediate I can react with hydroxyphosphine anion 2’ to produce 3 (left cycle). Under the acidic condition, an allyl nickel intermediate V undergoes the reaction with 2” to furnishes the final 1,3-dienyl isomer 4 (right cycle).
