Annulative π-extension (APEX) of 3-substituted indoles to pyrido[1,2-a]indoles is developed by using 4-oxo peroxides as π-extending reagents, which are employed as versatile C4 building blocks. This transformation is initiated by Brønsted acid-mediated Hock rearrangement of the peroxyl group. Notably, the pyrido[1,2-a]indole products are obtained by elimination of the indole moiety from the corresponding dihydropyrido[1,2a]indoles, which could be selectively formed at room temperature.

The ring opening of cyclopropanols is rarely used in multicomponent reactions. Herein we report the threecomponent reaction of cyclopropanols with alkenes and tert-butyl hydroperoxide (TBHP) catalyzed by an iron catalyst. This protocol enables the incorporation of both the β-carbonyl fragment and a peroxy unit across the CC double bond regioselectively, thus allowing an efficient, facile access to 5-oxo peroxides. Modification of the biologically active molecules and various downstream derivatizations of the peroxides are also demonstrated.

A manganese-catalyzed regioselective ring-opening peroxidation of cyclobutanols has been disclosed. With this protocol, the C(sp 3 )À OOBu-t bond could be efficiently constructed via the radical-mediated CÀ C bond cleavage/coupling, allowing the facile access to a variety of 4-oxo peroxides. Besides, the obtained peroxidation products could be readily transformed into other synthetically attractive skeletons.

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The isoxazole skeleton is one of key structural motifs, which displays widespread applications in drugs, agriculture, and synthetic intermediates. Herein, we disclose the DABCO‐mediated [4+1] cycloaddition of β,β‐dihalo peroxides and sodium azide for synthesis of multisubstituted isoxazoles. The cycloaddition proceeds through the formation of N−C and N−O bonds. This method shows excellent regioselectivity and good scalability.