Diiodosilane. 1. A novel reagent for deoxygenation of alcohols and ethers

Keinan, Ehud; Perez, Daniel

doi:10.1021/jo00231a004

Cited by 31 publications

(9 citation statements)

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“…The use of peracetic acid as oxidant in Baeyer–Villiger reactions on trifluoroacetophenone has also been previously reported . In this earlier work, phenyl trifluoroacetate was obtained with 5% yield after a reaction time of 5 h. A further paper from Kitazume and Kataoka reported 93% yield of the same compound after 1 h reaction time using m ‐CPBA as oxidation agent in refluxing CHCl 3 .…”

Section: Resultsmentioning

confidence: 70%

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A three‐step radiosynthesis of 6‐[¹⁸ F]fluoro‐L‐meta‐tyrosine starting with [¹⁸ F]fluoride

Meleán

Neumaier

Coenen

2015

Labelled Comp Radiopharmac

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The radiosynthesis of 6-[(18) F]fluoro-L-m-tyrosine has generally been performed by electrophilic radiofluorination, which exhibits several drawbacks. In the present work, a three-step radiochemical synthesis is described starting from [(18) F]fluoride. The synthetic sequence, including isotopic exchange, Baeyer-Villiger oxidation, and hydrolysis, were examined comparing four fluorobenzophenone derivatives as labeling precursors. Of those, (2S,5S)-tert-butyl 5-(5-acetyl-2-fluorobenzyl)-2-tert-butyl-3-methyl-4-oxoimidazolidine-1-carboxylate (1a) and (2S,5S)-tert-butyl 2-tert-butyl-5-(2-fluoro-5-(2,2,2-trifluoroacetyl)benzyl)-3-methyl-4-oxoimidazolidine-1-carboxylate (1d) proved to be the most suitable ones. 6-[(18) F]Fluoro-L-m-tyrosine was obtained with overall radiochemical yields of 8-13% and an enantiomeric excess of up to 98%.

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Section: Resultsmentioning

confidence: 70%

“…Using commercial DIS, the total conversion of the starting material was achieved after 8 h when 4 equivalents of DIS were used. The use of freshly prepared DIS reduced both the reaction time to 1.5 h and the amount of reagent necessary to 1.5 equivalents . In both cases, the isolated yield of compound 7 was about 80%.…”

Section: Resultsmentioning

confidence: 99%

A three‐step radiosynthesis of 6‐[¹⁸ F]fluoro‐L‐meta‐tyrosine starting with [¹⁸ F]fluoride

Meleán

Neumaier

Coenen

2015

Labelled Comp Radiopharmac

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“…To identify the active species, 1 H NMR of the 1:2 mixture of I 2 and PhSiH 3 in CD 2 Cl 2 was recorded (Figure a). The new peaks were assigned to PhSiH 2 I (δ H = 4.76 ppm), ISiH 3 (δ H = 3.55 ppm), and benzene (δ H = 7.38 ppm), which are consistent with Keinan’s report . PhSiH 2 I was also observed from the NMR analysis of the mixture of NIS and PhSiH 3 , while ISiH 3 and benzene were not detected (Figure b).…”

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confidence: 99%

“…These observations indicate that PhSiH 2 I is the possible active species of this reaction. Although the preparation of PhSiH 2 I is known, there are no reports on its reactivity to the best of our knowledge. , The optimization studies in Table indicate that the silyl iodide (Si–I) moiety of PhSiH 2 I is important for its catalytic activity (entries 5–7), although the Si–H moiety is not necessary (entries 9 and 10). Because the reaction of 1 equiv each of I 2 and PhSiH 3 generates 1 equiv of HI together with PhSiH 2 I, and an additional 1 equiv of PhSiH 3 reacts with HI to provide ISiH 3 and PhH, 10 mol % of I 2 and 20 mol % of PhSiH 3 in CH 2 Cl 2 (entry 4) were selected as the optimal conditions, which includes 10 mol % of PhSiH 3 to quench in situ generated HI from the reaction of I 2 and PhSiH 3 …”

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confidence: 99%

Intramolecular Hydroalkoxylation of Unactivated Alkenes Using Silane–Iodine Catalytic System

et al. 2015

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A novel catalytic system using I2 and PhSiH3 for the intramolecular hydroalkoxylation of unactivated alkenes is described. NMR study indicated that in situ generated PhSiH2I is a possible active catalytic species. This catalytic system allows an efficient intramolecular hydroalkoxylation of phenyl-, trialkyl-, and 1,1-dialkyl-substituted alkenes as well as a variety of unactivated monoalkyl- and 1,2-dialkyl-substituted alkenes at room temperature. Mechanistic consideration based on significant experimental observations is also discussed.

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“…Surprisingly, reduction of diketone 154 by treatment with freshly prepared diiodosilane (DIS) 70 at 40 o C for two days produced 165 in 76% yield and a trace amount of mono-reduced byproduct 166 (Scheme 40). It is interesting to note that the central carbon-carbon double bond in 154 was also reduced, giving rise to two additional sp 3 -hybridized carbons in 165.…”

Section: Reduction Of I 2 -Diketone 154mentioning

confidence: 99%

Synthesis of polycyclic aromatics having unusual molecular architectures via cascade cyclization reactions of enyne -allenes

Wang¹

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Synthesis of Polycyclic Aromatics Having Unusual Molecular Architectures via Cascade Cyclization Reactions of Enyne-Allenes YU-HSUAN WANG The C 2 −C 6 Schmittel cyclization reaction of the benzannulated enyne−allenes provides an efficient synthetic pathway for the construction of a variety of polycyclic aromatics. By starting from truxenone, the cascade cyclization reactions furnished several unusual and congested polycyclic compounds. The in situ generated enyne−allenes are key intermediates in these cyclization reactions. A new synthetic approach to 2,2′-disubstituted 1,1′-binaphthyls and related compounds was also successfully developed by using the benzannulated enediynes as precursors. These 1,1′-binaphthyls derivatives can serve as potential BINOL type ligands. The assembly of the enediynyl precursors from three separate aromatic fragments allows the possibility of placing a variety of functional groups at various positions of the 1,1′-binaphthyl system. A 12-step non-pyrolytic synthetic pathway employing the Schmittel cyclization reactions has been developed, leading to a bowl-shaped polycyclic aromatic hydrocarbon (PAH) having a 54-carbon framework of the surface of C 60. Incorporating of sp 3-carbons on the 54-carbon framework facilitates the connection of carbon atoms intramolecularly. iii Dedicated to My parents, brother, Leo, and sisters iv ACKNOWLEDGMENTS Firstly, I would like to express sincere appreciation to my advisor, Dr. Kung K. Wang, for his continuous support and encouragement during the past five years. His great patience and knowledge in chemistry guided me to solve so many problems. I was so pleased and lucky to have associated with this outstanding teacher and chemist. The way of his teaching not only benefits me academically but also led me to have a logical thinking when seeing through a problem. His enthusiasm and optimism are always my driving force to keep forward. My special thanks go to Dr. Jeffery Petersen for his significant work in X-ray crystal structure analysis. His work really helped me in identification of product structure which made my research keep forward. Also, Dr. Novruz.Akhmedov is greatly appreciated for his assistance in NMR studies of lots of my products. In addition, I would like to thank the rest of my research committee members, Dr. George A. O'Doherty, Dr. Peter M. Gannett, and Dr. John Penn for their valuable suggestions and discussion on my dissertation. My appreciation is also extended to the former and present group members, Dr. Hua Yang, Dr.

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Diiodosilane. 1. A novel reagent for deoxygenation of alcohols and ethers

Cited by 31 publications

References 1 publication

A three‐step radiosynthesis of 6‐[¹⁸ F]fluoro‐L‐meta‐tyrosine starting with [¹⁸ F]fluoride

A three‐step radiosynthesis of 6‐[¹⁸ F]fluoro‐L‐meta‐tyrosine starting with [¹⁸ F]fluoride

Intramolecular Hydroalkoxylation of Unactivated Alkenes Using Silane–Iodine Catalytic System

Synthesis of polycyclic aromatics having unusual molecular architectures via cascade cyclization reactions of enyne -allenes

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Diiodosilane. 1. A novel reagent for deoxygenation of alcohols and ethers

Cited by 31 publications

References 1 publication

A three‐step radiosynthesis of 6‐[18 F]fluoro‐L‐meta‐tyrosine starting with [18 F]fluoride

A three‐step radiosynthesis of 6‐[18 F]fluoro‐L‐meta‐tyrosine starting with [18 F]fluoride

Intramolecular Hydroalkoxylation of Unactivated Alkenes Using Silane–Iodine Catalytic System

Synthesis of polycyclic aromatics having unusual molecular architectures via cascade cyclization reactions of enyne -allenes

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A three‐step radiosynthesis of 6‐[¹⁸ F]fluoro‐L‐meta‐tyrosine starting with [¹⁸ F]fluoride

A three‐step radiosynthesis of 6‐[¹⁸ F]fluoro‐L‐meta‐tyrosine starting with [¹⁸ F]fluoride