Photochemical C–H Activation: Generation of Indole and Carbazole Libraries, and First Total Synthesis of Clausenawalline D

Alimi, Isak; Remy, Richard; Bochet, Christian G.

doi:10.1002/ejoc.201700300

Cited by 18 publications

(22 citation statements)

References 53 publications

(31 reference statements)

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“…In the same year, Bochet and co-workers achieved a total synthesis of an antimalarial alkaloid clausenawalline D ( 14-41 ) . As shown in Scheme , the [3 + 2] cycloaddition reaction of aryne precursor 14-37 with aromatic azide 14-38 gave a 1:1 mixture of regioisomers 14-39a and 14-39b in 82% yield.…”

Section: Syntheses Of Natural Products and Bioactive Moleculesmentioning

confidence: 98%

“…In the same year, Bochet and co-workers achieved a total synthesis of an antimalarial alkaloid clausenawalline D (14-41). 928 As shown in Scheme 310, the [3 + 2] cycloaddition reaction of aryne precursor 14-37 with aromatic azide 14-38 gave a 1:1 mixture of regioisomers 14-39a and 14-39b in 82% yield. Upon deprotection of the benzyl group on 14-39b, the resulting N-arylbenzotriazole 14-40 was subjected to photolysis conditions to furnish clausenawalline D (14-41) in 22% yield along with the formation of its regioisomer in the same amount.…”

Section: Cycloaddition Strategiesmentioning

confidence: 99%

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o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

2021

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Arynes are among the most active organic intermediates and have found numerous applications in expeditious preparation of substituted arenes. In the past 20 years, chemists have witnessed a resurgence in aryne chemistry, which is mainly attributed by the extensive utilization of Kobayashi's method, a fluoride-induced removal of the TMS group with concomitant departure of its ortho OTf group on o-silylaryl triflates. Nowadays, o-silylaryl triflates are the most frequently employed aryne precursors. This review provides an overview of the history of Kobayashi's method, its methodological achievements, and its applications in the synthesis of natural products, bioactive molecules, and polycyclic aromatic hydrocarbons.

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Section: Syntheses Of Natural Products and Bioactive Moleculesmentioning

confidence: 98%

Section: Cycloaddition Strategiesmentioning

confidence: 99%

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

2021

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“…Pyrolysis , and photolysis − of 1-arylbenzotriazoles 14 yield carbazoles 18 in high yields (Scheme ). Diazo compounds 15 have been detected as intermediates in matrix photolysis reactions .…”

Section: Resultsmentioning

confidence: 99%

“…7 The triplet diradicals 16E,Z have been characterized by ESR spectroscopy in the photolysis of 7 at 77 K. 17 Compound 14b was examined by FVP at 780−1100 °C, 13 compound 14c by low-pressure Hg arc photolysis, 14,15 and 14d by photolysis at 254 nm. 16 Involvement of benzazirines 17 would have led to formation of positional isomers 19 of the carbazoles, and such isomers have not been detected in either pyrolysis or photolysis reactions. This excludes the involvement of benzazirines 17.…”

Section: ■ Introductionmentioning

confidence: 99%

Benzotriazoles and Triazoloquinones: Rearrangements to Carbazoles, Benzazirines, Azepinediones, and Fulvenimines

et al. 2021

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The denitrogenative rearrangements of several types of benzotriazoles were investigated by DFT (B3LYP/6-311G(d,p)) and CASPT2(10,10)sp/6-311G(d,p) calculations. The Graebe–Ullmann synthesis of carbazoles 18 by pyrolysis or photolysis of 1-arylbenzotriazoles 14 proceeds without the involvement of benzazirines and without Wolff-type ring contraction to fulvenimines. However, 1-aryltetrahydrobenzotriazoles undergo both cyclization to tetrahydrocarbazole and ring contraction. Triazoloquinones like 34 undergo predominant ring contraction to aminofulvenediones like 38 and also ring expansion to azepinediones like 40 and cyclization to N-arylbenzaziridinediones 39, whereas carbazolediones are not formed. Denitrogenation of 1-methylbenzotriazole 64 results in a facile 1,2-H shift with formation of N-phenylmethanimine 67. 1-Cyanobenzotriazole 71 undergoes destructive pyrolysis with charring, and the calculations predict the occurrence of several low-activation energy reaction pathways.

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“…Various substituted carbolines were obtained from benzotriazoles 265.6 and azines bearing a leaving group at C2 in improved yields in a shorter reaction time. In 2017, Bochet and co-workers utilized the photochemical Graebe–Ullmann reaction of benzotriazoles 265.8 to synthesize a variety of carbazole derivatives. Additionally, they accomplished the first synthesis of the antimalarial alkaloid clausenawalline D ( 265.9 ).…”

Section: Denitrogenative Transformations Of Benzotriazolesmentioning

confidence: 99%

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

2022

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Readily accessible and shelf-stable 1,2,3-triazole and its analogues such as pyridotriazole, triazoloindole, benzotriazole, and thiadiazole exist in equilibrium with their ring-opened isomers, viz., diazo compounds. These ring-opened isomers could be trapped by various metal catalysts (e.g., Rh, Pd, Cu, Co, Ag, etc.) to generate the corresponding metal carbenoids with extrusion of nitrogen. As a consequence, these unique N-heterocycles facilitate access to a realm of N-containing complex structural motifs of biological importance through denitrogenative transformations such as transannulations, insertions, ylide formation, and rearrangements by trapping of the metal carbenoids with a diverse range of coupling partners (e.g., alkenes, alkynes, nitriles, carbo/heterocycles, X–H/C–X bonds, etc.). Hence, suitably substituted triazole derivatives have emerged as efficient surrogates of diazo compounds for the generation of reactive metal carbenoids during the past decades. In this comprehensive review, we aim to discuss in detail the remarkable advancement in their synthesis and synthetic applications.

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Photochemical C–H Activation: Generation of Indole and Carbazole Libraries, and First Total Synthesis of Clausenawalline D

Cited by 18 publications

References 53 publications

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

Benzotriazoles and Triazoloquinones: Rearrangements to Carbazoles, Benzazirines, Azepinediones, and Fulvenimines

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

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