Pd/NBE-Catalyzed One-Pot Modular Synthesis of Polycyclic Fused δ-Lactams and Investigation of Room-Temperature Phosphorescence

Abstract

The advancement of sophisticated synthetic methodologies that streamline reaction processes while enhancing molecular complexity is a perpetual necessity in the realm of chemistry. Catalytic one-pot cascade methodologies play a crucial role in the efficient construction of intricate molecules with exceptional chemoselectivity. Herein, we present a one-pot approach for the synthesis of polycyclic fused δ-lactams via the sequential phosgenation, Pd/NBE-catalyzed ortho-carbamoylation/ ipso-Heck-type cyclization, and C−H activation from readily available aryl halides, amines, and triphosgenes. This reaction stands out as the first example of the in situ carbamoyl chloride formation from readily available amine precursors, presenting an alternative to existing transformations involving carbamoyl chlorides. The practical significance of these methodologies is showcased by the efficient synthesis of 81 polycyclic fused δlactams in a rapid and economically favorable manner, without the need for intermediate purification. Moreover, these transformations were scalable and compatible with various natural products and pharmaceuticals, further underscoring the effectiveness of this strategy. The relatively rigid and coplanar structure displayed in our synthesized polycyclic fused δ-lactams exhibits distinct room-temperature phosphorescence characteristics, which have been utilized in anticounterfeiting and high-securitylevel data encryption.