Palladium‐Catalyzed Cascade Cyclization for the Synthesis of Fused Benzo‐Aza‐Oxa‐[5‐6‐5] Tetracycles

Abstract

A novel and expedient cascade strategy has been demonstrated for the synthesis of fused benzo‐aza‐oxa‐[5‐6‐5] tetracycles in high yields and diastereoselectivities (up to 20 : 1 dr). The strategy was fulfilled through palladium‐catalyzed oxidative convergent assembly of functionally divergent anilines and 3‐butenoic acid with five chemical bonds constructed. Coupled with control experiments and deuterium labelled studies, DFT calculations were performed for the proposed mechanism. The utility of the illustrated strategy is emphasized by gram‐scale syntheses, late‐stage functionalization, and the transformation to a key core of natural products such as martinellic acid and seneciobipyrrolidine.

Photoinduced Arene C−H Amination with Ammonia: A Practical and Regioselective Strategy for Primary Amines

“…asc.wiley-vch.de [5-6-5] tetracycle 7 and triazoles derivatives 8 could also be successfully achieved from 3 aj. [19][20] To better study the mechanism of the reaction, the radical scavenger experiment was conducted. When TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) was added under standard conditions, the TEMPO-trapped product 9 was detected by HR-MS (High-Resolution Mass Spectrometry), revealing bond of the aryl sulfonium salts was cleaved under visible light irradiation and resulted in the formation of the aryl radical intermediate.…”

“…Symmetrical amide 6 could be obtained from the copper‐catalyzed transamidation of 3 aj with urea [18] . Additionally, fused benzo‐ aza ‐ oxa ‐[5‐6‐5] tetracycle 7 and triazoles derivatives 8 could also be successfully achieved from 3 aj [19–20] …”

Palladium‐Catalyzed anti‐Markovnikov Halosulfonamidation of Unactivated Alkene†

“…The palladium‐catalyzed aminative difunctionalization of alkenes to incorporate an amine group as well as another functional group has been employed as a robust methodology to construct highly functionalized alkylamines of high value in medicinal and material chemistry with benign efficiency in synthetic routine. [ 1‐7 ] When halogen is introduced in a position vicinal to a sulfonamide group, this halosulfonamidation not only results in improvements in biological applications of sulfonamide scafford, [ 8‐10 ] but also provides the platform for further transformations into various amine derivatives, e.g ., aziridines and diamines. [ 11‐18 ]…”

Radical Decarboxylative 1,2,3-Trifunctionalization of 3-Enoic Acids via 1,4-Imino-N Shift: A Modular Approach to Functionalized 3,4-Dihydroisoquinolines

“…Alkenyl carboxylic acids, especially 3-enoic acids, are readily accessible simple building blocks which play important roles in organic transformation. 11,12 Their functional group conversion mainly focuses on the decarboxylative functionalization only as carboxylic acids 13 or the 1, 2-difunctionalization just as alkenes 14 . While the simultaneous combination of the decarboxylative functionalization and the alkene 1,2-difunctionalization leading to direct 1,2,3trifunctionalization of 3-enoic acids in a reaction, to our best knowledge, has never been achieved (Figure 1B).…”