Sodium-Metal-Promoted Reductive 1,2-<i>syn</i>-Diboration of Alkynes with Reduction-Resistant Trimethoxyborane

Ito, Shiori; Fukazawa, Mizuki; Takahashi, Fumiya; Nogi, Keisuke; Yorimitsu, Hideki

doi:10.1246/bcsj.20200110

Cited by 29 publications

(22 citation statements)

References 65 publications

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“…Organosodium chemistry has long been overshadowed by wellestablished organolithium chemistry. Alhough there has been some recent renewed interest in the use of organosodium compounds for organic synthesis [46][47][48][49][50][51][52][53][54][55][56][57][58] , the lack of general and reliable preparation methods has hindered the development of truly useful reactions. To change this status quo, we have demonstrated in this paper that efficient halogen-sodium exchange reactions are now possible~80 years after the seminal study 14 , using neopentylsodium as a key metalating reagent, to expand the repertoire of available organosodium compounds greatly 59 .…”

Section: Discussionmentioning

confidence: 99%

Halogen–sodium exchange enables efficient access to organosodium compounds

et al. 2021

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With sodium being the most abundant alkali metal on Earth, organosodium compounds are an attractive choice for sustainable chemical synthesis. However, organosodium compounds are rarely used—and are overshadowed by organolithium compounds—because of a lack of convenient and efficient preparation methods. Here we report a halogen–sodium exchange method to prepare a large variety of (hetero)aryl- and alkenylsodium compounds including tri- and tetrasodioarenes, many of them previously inaccessible by other methods. The key discovery is the use of a primary and bulky alkylsodium lacking β-hydrogens, which retards undesired reactions, such as Wurtz–Fittig coupling and β-hydrogen elimination, and enables efficient halogen–sodium exchange. The alkylsodium is readily prepared in situ from neopentyl chloride and an easy-to-handle sodium dispersion. We believe that the efficiency, generality, and convenience of the present method will contribute to the widespread use of organosodium in organic synthesis, ultimately contributing to the development of sustainable organic synthesis by rivalling the currently dominant organolithium reagents.

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Section: Discussionmentioning

confidence: 99%

Halogen–sodium exchange enables efficient access to organosodium compounds

et al. 2021

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“…The same group extended the methodology to the reductive diboration of alkynes with high Z-selectivity (Scheme 23). 49 The reaction proceeded in good yield for diaryl, aryl alkyl, and aryl silyl alkynes, enynes, and a terminal alkyne (phenylacetylene), and could be conducted on gram scale. A mechanism analogous to the previous report (see Scheme 22) was proposed.…”

Section: Special Topic Synthesismentioning

confidence: 99%

Recent Advances in the Use of Sodium Dispersion for Organic Synthesis

De¹,

Asako²,

Ilies³

2021

Synthesis

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This short review describes the recent emergence of organosodium chemistry, motivated by the requirements of modern synthetic chemistry for sustainability, and powered by the use of sodium dispersion, a form of sodium that is commercially available, easy to handle, and has a large active surface area. We present recent preparation methods of oraganosodium compounds using sodium dispersion, and their applications to synthesis; sodium amides and phosphides are also briefly discussed.

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“…We have been interested in the development of alkali-metal-promoted reductive transformations of unsaturated compounds [20][21][22][23][24] by using reduction-resistant electrophiles as key reagents. [25][26][27] In one hand, this class of electrophiles such as trialkoxyboranes are resistant to single electron reduction so that they can coexist in the same pot where the reduction of unsaturated substrates takes place. On the other hand, they are sufficiently electrophilic to immediately trap the unstable anions thus formed.…”

Section: Introductionmentioning

confidence: 99%

Reductive anti-dimagnesiation and dialumination of alkynes: Synthesis and reactions of trans-1,2-dimetalloalkenes

Takahashi

Kurogi

Yorimitsu

2022

Preprint

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Given the great significance of polar reactive organometallic species in synthesis for more than one century, generation and use of stereodefined 1,2-dimetallated alkenes should be fascinating yet has been very challenging. Here we report reductive anti-1,2-dimetalation of alkynes to easily and stereoselectively generate trans-1,2-dimagnesio- and 1,2-dialuminoalkenes that are difficult to prepare, reasonably stable, and thus useful for organic synthesis. The key for the success is the use of sodium dispersion as a powerful reducing agent and organomagnesium and organoaluminum halides as reduction-resistant electrophiles counterintuitively. Highly nucleophilic 1,2-dimagnesioalkenes serve as dual Grignard reagents and react with various electrophiles to afford anti-difunctionalized alkenes. Interestingly, 1,2-dialuminoalkenes react with paraformaldehyde with dearomatization of the aryl moieties to form the corresponding dearomatized 1,4-diols, the overall reaction being regarded as alkynyl-directed dearomatization of arenes. Our anti-1,2-dimetalation including structural and computational investigation provides a new powerful tool and unique insight in the development of organometallic chemistry and organic synthesis.

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Sodium-Metal-Promoted Reductive 1,2-syn-Diboration of Alkynes with Reduction-Resistant Trimethoxyborane

Cited by 29 publications

References 65 publications

Halogen–sodium exchange enables efficient access to organosodium compounds

Halogen–sodium exchange enables efficient access to organosodium compounds

Recent Advances in the Use of Sodium Dispersion for Organic Synthesis

Reductive anti-dimagnesiation and dialumination of alkynes: Synthesis and reactions of trans-1,2-dimetalloalkenes

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