Intermolecular Iodofluoroalkylation of Unactivated Alkynes and Alkenes Mediated by Manganese Catalysts

Ji, Yun‐Xing; Wang, Lujun; Guo, Wei‐Si; Bi, Qirui; Zhang, Bo

doi:10.1002/adsc.201901556

“…All reactions were performed as described in Table 1 Preparation of tertiary iodides and lactones. Due to the instability of tertiary iodide under most reactions conditions reported for ATRA reactions (light, heat), iodine ATRA-reactions involving the formation of a tertiary iodides have so far only been achieved at room temperature using triethylborane [59][60][61] and Mn2(CO)10 [62] initiation. Surprisingly, running the reaction between the protected 4-methylenepiperine 1h and ethyl 2-iodoacetate 2a under our mild DTBHN conditions afforded the tertiary iodide 16 in an excellent 91% yield (Scheme 4, top).…”

Section: Resultsmentioning

confidence: 99%

Methyl Radical Initiated Kharasch and Related Reactions

Tappin¹,

Renaud²

2020

Preprint

0

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An improved procedure to run halogen atom and related chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di-tert-butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methyl radicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating greatly product purification by either flash column chromatography or distillation. In addition, remarkably simple and mild reaction conditions (refluxing EtOAc during 30 minutes under normal atmosphere) and a low excess of the radical precursor reagent (2.0 equivalents) make this protocol particularly attractive for preparative synthetic applications. This initiation procedure has been demonstrated with a broad scope since it works efficiently to add a range of electrophilic radicals generated from iodides, bromides, selenides and xanthates over a range of unactivated terminal alkenes. A diverse set of radical trap substrates exemplifies a broad functional group tolerance. Finally, di-tert-butyl peroxyoxalate (DTBPO) is also demonstrated as alternative source of tert-butoxyl radicals to initiate these reactions under identical conditions which gives gaseous byproducts (CO2).

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“…Preparation of tertiary iodides and lactones. Due to the instability of tertiary iodide under most conditions reported for ATRA reactions (light, heat), iodine ATRA-reactions involving the formation of a tertiary iodides have so far only been achieved at room temperature using triethylborane [59][60][61] and Mn2(CO)10 [62] initiation. Surprisingly, running the reaction between the protected 4-methylenepiperine 1h and ethyl 2-iodoacetate 2a under our mild DTBHN conditions afforded the tertiary iodide 16 in an excellent 91% yield (Scheme 4, top).…”

Section: Resultsmentioning

confidence: 99%

Methyl Radical Initiated Kharasch and Related Reactions

Tappin

¹

,

Renaud

²

2020

Preprint

0

View full text Add to dashboard Cite

An improved procedure to run halogen atom and related chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di-tert-butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methyl radicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating greatly product purification by either flash column chromatography or distillation. In addition, remarkably simple and mild reaction conditions (refluxing EtOAc during 30 minutes under normal atmosphere) and a low excess of the radical precursor reagent (2.0 equivalents) make this protocol particularly attractive for preparative synthetic applications. This initiation procedure has been demonstrated with a broad scope since it works efficiently to add a range of electrophilic radicals generated from iodides, bromides, selenides and xanthates over a range of unactivated terminal alkenes. A diverse set of radical trap substrates exemplifies a broad functional group tolerance. Finally, di-tert-butyl peroxyoxalate (DTBPO) is also demonstrated as alternative source of tert-butoxyl radicals to initiate these reactions under identical conditions which gives gaseous byproducts (CO2).

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“…[18][19][20] Besides the frequently encountered Ir and Ru complexes, Mn complexes are viable photosensitizers for ATAR reactions. In 2020, Bi, Zhang, and co-workers 24 developed a strategy for the Mn photoredox catalyzed iodoperfluoroalkylation of alkynes/alkenes with perfluoroalkyl iodides (Scheme 4). In the presence of earth-abundant and inexpensive manganese complex Mn 2 (CO) 10 , this ATRA reaction proceeded smoothly under irradiation by blue LEDs; a series of alkenes and alkynes bearing various functional groups and various perfluoroalkyl iodides were well-tolerated under the reaction conditions and gave a variety of perfluorinated alkanes or alkenes in good yields with excellent regio-and E/Z selectivities.…”

Section: Short Review Synthesismentioning

confidence: 99%

Recent Advances in Photoinduced Perfluoroalkylation Using Perfluoroalkyl Halides as the Radical Precursors

Tang¹,

Liu²,

Liu³

et al. 2022

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Perfluoroalkylation is one of the most important methods for the introduction of multiple fluorine atoms into organic molecules in a single step. The use of photoinduced technology is a common strategy that uses the outstanding oxidation or reduction ability of a photoredox catalyst in its excited state to generate perfluoroalkyl radicals from perfluoroalkyl halides. The perfluoroalkyl radicals thus obtained can undergo various subsequent reactions under mild conditions, such as ATRA reaction of alkenes, alkynes, and 1,n-enynes; carbo/heteroperfluoroalkylation of alkenes and isocyanides; and C–H/F perfluoroalkylation. This allows the expedient incorporation of various perfluoroalkyl groups into the molecular motifs. Perfluorinated functional groups are still in demand in pharmaceutical and material sciences; this short review discusses recent advances in photoinduced perfluoroalkylation methodologies and technologies.1 Introduction2 Photocatalytic Perfluoroalkylation of Alkenes, Alkynes, and 1,n- Enynes3 Photocatalytic Carboperfluoroalkylation or Heteroperfluoroalkylation of Alkenes, Alkynes, Isocyanides, and Hydrazones4 Photocatalytic ATRE Reactions of Alkenes with Perfluoroalkyl Halides5 Photocatalytic C–X (X = H, F) Bond Perfluoroalkylation6 Continuous Flow Strategies in Photocatalytic Perfluoroalkylation7 Conclusions

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Intermolecular Iodofluoroalkylation of Unactivated Alkynes and Alkenes Mediated by Manganese Catalysts

Cited by 33 publications

References 56 publications

Methyl Radical Initiated Kharasch and Related Reactions

Methyl Radical Initiated Kharasch and Related Reactions

Methyl Radical Initiated Kharasch and Related Reactions

Recent Advances in Photoinduced Perfluoroalkylation Using Perfluoroalkyl Halides as the Radical Precursors

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