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

Chiral Ga4L6 assembly Ga-4(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 Ga-4(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.