This review summarizes the most recent progress made in C–H bond activation-initiated spiroannulation reactions and their applications in the construction of structurally diverse and biologically valuable spirocyclic scaffolds.
The advancements in the synthesis of nitrogen-containing heterocycles via Rh(III)-catalyzed chelation-assisted tandem C–H activation/carbene insertion/annulation with diazo compounds as carbene precursors have been summarized.
A redox-neutral access to spirooxazine-pyrans has been realized via Rh(III)-catalysed [3+3] cascade spirocyclization of benzo[b][1,4]oxazines and 1-diazonaphthalen-2(1H)-ones under extremely mild reaction conditions.
The present review summarizes the recent advances (2018–2023) in stereoselective annulation involving p-benzoquinones for the construction of fused, spiro and bridged/cage frameworks.
An unusual Au(I)/Sc(III)-co-catalyzed tandem spiroannulation/cycloisomerization of 3-(2-ethynylaryl)-N-tosylaziridine-2,2-diesters with indoles has been reported. A variety of 5H-benzo[b]carbazoles were obtained in moderate to good yields (30–88%).