A Three-Layer Transformation Strategy toward Functionalized Fused Hydantoins and Diketopiperazines

We present mAUCy (modified Asinger-Ugi cyclization), a scalable three-layer strategy enabling rapid synthesis of diverse thiazolo hydantoins and diketopiperazines. Beginning from 3-thiazolines via a modified Asinger reaction, followed by an Ugi-Joullié multicomponent reaction and base-induced annulation, the method delivers complex compounds in less than 3 h. Operable on a multigram scale without chromatography, it allows telescoped one-pot processing, a broad substrate scope, and late-stage modifications. Single-crystal analysis confirmed the scaffold structures.