Complex Polyheterocycles and the Stereochemical Reassignment of Pileamartine A via Aza-Heck Triggered Aryl C–H Functionalization Cascades

Abstract

Structurally complex benzo-and spiro-fused N-polyheterocycles can be accessed via intramolecular Pd(0)-catalyzed alkene 1,2-aminoarylation reactions. The method uses N-(pentafluorobenzoyloxy)carbamates as the initiating motif, and this allows aza-Heck-type alkene amino-palladation in advance of C−H palladation of the aromatic component. The chemistry is showcased in the first total synthesis of the complex alkaloid (+)-pileamartine A, which has resulted in the reassignment of its absolute stereochemistry.

Hydroamination, Aminoboration, and Carboamination with Electrophilic Amination Reagents: Umpolung-Enabled Regio- and Stereoselective Synthesis of N-Containing Molecules from Alkenes and Alkynes

“…Additionally, in the case with 4-pentenylamine derivative 65, the intramolecular aromatic C−H serves as the internal carbon nucleophile to afford the complex N-heterocycle 66 under similar conditions (Scheme 29). 85 Following N−O oxidative addition and alkene insertion, the formed alkylpalladium is trapped with the intramolecular aromatic C−H to finally deliver the tricyclic system 66.…”

Construction of NH‐Unprotected Spiropyrrolidines and Spiroisoindolines by [4+1] Cyclizations of γ‐Azidoboronic Acids with Cyclic N‐Sulfonylhydrazones

“…[9] Forthese reasons,the development of flexible methods for the synthesis of structurally diverse spiropyrrolidines have concentrated great interest in the recent years. [10][11][12][13][14][15][16][17][18] N-Sulfonylhydrazones are very attractive derivatives of carbonyl compounds,that have been extensively employed as precursors of diazo compounds in avariety of metal-catalyzed as well as non-catalytic transformations. [19][20][21][22][23] In particular,the transition-metal free reaction between N-sulfonylhydrazones and boronic acids,f irst reported by our group, [24] is av ery useful C À Cb ond forming reaction that has found ample application in organic synthesis as am ethod to generate molecular diversity from carbonyl compounds.…”

“… [9] For these reasons, the development of flexible methods for the synthesis of structurally diverse spiropyrrolidines have concentrated great interest in the recent years. [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]…”

N-Tosyl-1,2,3-triazoles as Scaffolds for Morpholines: The Total Synthesis of (–)-Chelonin A

“…(−)-Chelonin A (5), chelonin B (6), (+)-chelonin C (7) and (+)bromochelonin B (8) were first isolated in 1991 from the marine sponge Chelonaplysilla sp. (Figure 2).…”