Improved scope and diastereoselectivity of C–H activation in an expanded supramolecular host

Chiral Ga₄L₆ assembly Ga₄(L^N)₆ encapsulates cationic iridium half-sandwich complexes that activate aldehyde C–H bonds to form chiral, strongly bound piano-stool complexes. Herein, we report the expanded scope of the larger Ga₄(L^P)₆ host in mediating this transformation. The larger assembly significantly improves both the scope and the diastereoselectivity of this organometallic transformation generally, while substrate-specific interactions demonstrate that host size is an important, but not definitive, factor in determining diastereoselectivity.