Leiyang Lv

Benzannulation of Indoles to Carbazoles and Its Applications for Syntheses of Carbazole Alkaloids

A novel and efficient method for the benzannulation of indoles to carbazoles is reported. γ-Carbonyl tert-butylperoxide is applied as a new diene building block for the π-extension of simple indoles. The synthetic utility of this method is demonstrated by concise and selective total syntheses of naturally occurring carbazole alkaloids, olivacine, and asteropusazole A.

Total Synthesis of (±)‐Clavilactones A, B, and Proposed D through Iron‐Catalyzed Carbonylation–Peroxidation of Olefin

Biologically significant clavilactones A, B, and the previously proposed D have been synthesized through iron-catalyzed carbonylation-peroxidation of a 1,5-diene. Three steps from aldehydes, alkenes, and tert-butylhydroperoxide build up α,β-epoxy-γ-butyrolactone skeleton as a key building block for synthesis of clavilactone family and its derivatives. Based on our results, the structure of the proposed clavilactone D is not correct and requires revision.

Iron-Catalyzed Acylation-Oxygenation of Terminal Alkenes for the Synthesis of Dihydrofurans Bearing a Quaternary Carbon

Iron-catalyzed acylation-oxygenation of terminal alkenes is reported. Acyl radicals generated by the oxidation of aldehydes add to terminal alkenes and followed by intramolecular oxygenation give functionalized 2,3-dihydrofuran derivatives bearing a quaternary carbon.

Iron-Catalyzed Radical [2 + 2 + 2] Annulation of Benzene-Linked 1,7-Enynes with Aldehydes: Fused Pyran Compounds.

An iron-catalyzed radical [2 + 2 + 2] annulation of benzene-linked 1,7-enynes with aldehydes has been developed. With this method, a variety of fused [6.6.6] pyran molecules are built in an efficient and selective manner. The aldehydic radical-mediated strategy exhibits a particularly attractive dual role, which triggers and terminates the domino cyclization.

Iron-Catalyzed Convergent Radical Cyclization of Aldehydes with Two Alkenes to 3,4-Dihydropyrans.

A novel convergent radical cyclization of an aldehyde with two alkenes has been developed. With this method, polyfunctionalized 3,4-dihydropyrans are built in an efficient and selective manner. The iron-catalyzed redox radical recombinations are proposed for the formation of a 3,4-dihydropyran skeleton.

Fe-Catalyzed Cross-Dehydrogenative Coupling Reactions

Cross-dehydrogenative coupling (CDC), which enables the formation of carbon–carbon (C–C) and C–heteroatom bonds from the direct coupling of two C–H bonds or C–H/X–H bonds, represents a new state of the art in the field of organic chemistry. Iron, a prominent metal, has already shown its versatile application in chemical synthesis. This review attempts to provide a comprehensive understanding of the evolution of cross-dehydrogenative coupling via iron catalysis, as well as its application in synthetic chemistry.

Iron-catalyzed decarbonylation initiated [2 + 2 + m] annulation of benzene-linked 1,n-enynes with aliphatic aldehydes

An iron-catalyzed decarbonylation initiated [2 + 2 + m] annulation of benzene-linked 1,n-enynes with aliphatic aldehydes has been developed. These divergent annulations allow the one-step and efficient synthesis of various fused- or spiro-polycyclic frameworks. Tertiary aldehydes undergo decarbonylation/β-C(sp3)–H cleavage to afford [2 + 2 + 2] cyclization products, whereas secondary aldehydes undergo decarbonylation/α-C(sp3)–H cleavage to generate [2 + 2 + 1] cyclization products.

Iron-Catalyzed Divergent Tandem Radical Annulation of Aldehydes with Olefins toward Indolines and Dihydropyrans

Iron-catalyzed divergent tandem radical annulations of aldehydes with olefins are reported. The new strategy allows the rapid and efficient construction of various multifunctionlized indolines (R = Ar) and dihydropyrans (R = Me), which are significant skeletons in bioactive natural products and pharmaceuticals. The substituents of tertiary amines play vital roles to facilitate the desired transformation. Mechanistic studies on indoline formation disclose that the homolytic cleavage of the carbonyl C-H bond might be involved in the rate-determining step, while dissociation of the aromatic C-H bond was most likely included in the product-determining step.

Copper-catalyzed tandem trifluoromethylation–cyclization of olefinic carbonyls: synthesis of trifluoromethylated 2,3-dihydrofurans and 3,4-dihydropyrans

A copper-catalyzed trifluoromethylation–cyclization of olefinic carbonyls was developed. With this method, a variety of 2,3-dihydrofuran and 3,4-dihydropyran derivatives containing a CF3 group were selectively obtained in moderate to good yields. This chemistry represents a rare example of direct construction of trifluoromethylated oxygen-containing heterocycles via the combination of radical trifluoromethylation with endo-type radical addition to carbonyls.

Total Synthesis and Structure Revision of (±)-Clavilactone D Through Selective Cyclization of an α,β-Dicarbonyl Peroxide

The structure of (±)-clavilactone D was revised, and the synthesis was achieved in seven steps from a substituted benzaldehyde. The key step was the base-catalyzed cyclization of an α,β-carbonyl peroxide, which was obtained by an iron-catalyzed three-component reaction of a benzaldehyde, an alkene, and TBHP. NaBH4-mediated reductive lactonization of the resulting cis-dicarbonyl epoxide led to the α,β-epoxy-γ-butyrolactone skeleton highly stereoselectively. The synthesis provides a concise, reliable, and practical route to the revised structure of clavilactone D.