Synthesis of ¹⁰B-enriched 2,1-borazaronaphthalenes from o-aminostyrenes and ¹⁰BF₃

Herein we present a practical approach for preparing 10B-enriched 2,1-borazaronaphthalenes from o-aminostyrenes and 10BF3 (the primary source of boron-10) in the presence of chlorosilane. The synthetic potential of this transformation is showcased by the satisfactory substrate scope, scale-up reaction and late-stage modification of 10B-enriched molecules. The preliminary mechanistic studies suggest that this 10B transformation may involve the formation of boron chloride species and subsequent cyclization with o-amino-styrene.