Described herein is an unprecedented N-alkylation-initiated redox-neutral [5 + 2] annulation of 3-alkylindoles with o-aminobenzaldehydes via a cascade N-alkylation/dehydration/[1,5]-hydride transfer/Friedel–Crafts alkylation sequence. A series of indole-1,2-fused 1,4-benzodiazepines are facilely constructed in moderate to good yields in one step. This protocol features excellent regioselectivity, metal-free conditions, high step economy, and wide substrate scope.

Herein, we report the first redox-neutral and transition-metal-free β-C(sp 3 )−H functionalization of cyclic amines via a consecutive intermolecular hydride transfer process. A series of N-aryl pyrrolidines and N-aryl 1,2,3,4tetrahydropyridines decorated with CF 3 and carboxylic ester functionalities are directly accessed in good yields from pyrrolidines and piperidines. This work pushes forward the application of the intermolecular hydride transfer strategy in one-step assembly of molecular complexity.

Hexafluoroisopropanol has been demonstrated as the versatile promoter for redox-neutral α-C(sp 3 )−H functionalization of cyclic amines via the cascade [1,5]hydride transfer/cyclization strategy. A wide range of cyclic amines are functionalized into bioactive tetrahydroquinolines, quinazolines, benzoxazines, and benzotriazepines in moderate to excellent yields. This protocol features additive-free conditions, operational simplicity, and wide substrate scope.

The redox-neutral cascade dearomatization of indoles with o-aminobenzaldehydes has been realized via the hydride transfer strategy, achieving the condition-and substrate-controlled divergent synthesis of tetrahydroquinoline-fused spiroindolenines. The integration of hydride transfer-involved C(sp 3 )−H functionalization with dearomatization provides a promising platform for the construction of structurally diverse molecules.

The organocatalytic dearomative [4 + 2] cycloadditions of biomass-derived 2,5-dimethylfuran with ortho-quinone methides were developed, affording two diffferent types of multisubstituted chromanes in high yields and excellent diastereoselectivities. The controllable synthesis of these two types of multisubstituted chromanes could be achieved by succinctly varying the reaction conditions.