meso‐Hydrazines could be desymmetrised by ring‐opening reactions by using various metal catalysts to form substituted cyclopentenes, which have a high synthetic potential. Herein, we report the asymmetric copper‐catalysed ringopening of a range of polycyclic hydrazines with trialkylaluminiumreagents and SimplePhosligands with both high isolated yields and enantioselectivities of up to 95 %.
trimethylaluminum in "noncoordinating" solvents, leading to the corresponding aminophosphine which is the real ligand in copper-catalyzed asymmetric transformations. This artifact explains the experimental differences in the asymmetric ringopening of meso bicyclic hydrazines using dialkylzinc or trialkylaluminum reagents as nucleophiles.