Practical synthesis and applications of benzoboroxoles

Gunasekera, Dinara S.; Gerold, Dennis J.; Aalderks, Nathan S.; Chandra, J. Subash; Maanu, Christiana A.; Kiprof, Paul; Zhdankin, Viktor V.; Reddy, M. Venkat Ram

doi:10.1016/j.tet.2007.06.099

Cited by 38 publications

(30 citation statements)

References 32 publications

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“…The most common substrates in this type of reaction were ortho-bromobenzyl alcohols, which reacted with butyllithium to give corresponding phenyllithium compounds [14,22,32]. The next steps were: reaction with trialkyl borate, hydrolysis and a subsequent spontaneous dehydration (method B1).…”

Section: Methods B: Introduction Of Boronic Group Into Benzyl Alcoholmentioning

confidence: 99%

“…A modification of this method is the initial reaction of benzyl alcohol with one mole of sodium hydride, and further reactions as in method B1 (method B2) [32]. Alternatively, the hydroxyl group can be protected prior to the addition of butyllithium.…”

Section: Methods B1mentioning

confidence: 99%

“…Tetrahydropyranyl (THP) [22] or methoxymethyl (MOM) [10] groups were applied as the protecting group (methods B2a and B2b, respectively). ortho-Bromobenzyl alcohols used as substrates in these reactions can be obtained by the reduction of corresponding benzaldehydes or their reaction with Grignard reagents [32].…”

Section: Methods B1mentioning

confidence: 99%

“…The title compounds react with aryl halides in Suzuki-Miyaura cross-coupling to form biaryls with hydroxymethyl group at ortho position [24,32] (Scheme 6).…”

Section: Reactivity Of B-c Bondmentioning

confidence: 99%

“…The most important synthetic application of benzoxaboroles is their use in Suzuki-Miyaura coupling (Scheme 6) [22,24,32,[38][39][40][42][43][44][45][46][47][48][49]. In this reaction benzoxaboroles or their esters react with aryl halides to give ortho-arylsubstituted benzyl alcohols in high yield.…”

Section: Organic Synthesismentioning

confidence: 99%

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Benzoxaboroles – Old compounds with new applications

Adamczyk‐Woźniak

Cyrański

Żubrowska

et al. 2009

Journal of Organometallic Chemistry

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Section: Methods B: Introduction Of Boronic Group Into Benzyl Alcoholmentioning

confidence: 99%

Section: Methods B1mentioning

confidence: 99%

Section: Methods B1mentioning

confidence: 99%

“…The title compounds react with aryl halides in Suzuki-Miyaura cross-coupling to form biaryls with hydroxymethyl group at ortho position [24,32] (Scheme 6).…”

Section: Reactivity Of B-c Bondmentioning

confidence: 99%

Section: Organic Synthesismentioning

confidence: 99%

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Benzoxaboroles – Old compounds with new applications

Adamczyk‐Woźniak

Cyrański

Żubrowska

et al. 2009

Journal of Organometallic Chemistry

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Substituent Effects on Oxidation‐Induced Formation of Quinone Methides from Arylboronic Ester Precursors

Cao

Christiansen

Peng

2013

Chemistry A European J

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A series of arylboronic esters containing different aromatic substituents and various benzylic leaving groups (Br or N(+)Me3Br(-)) have been synthesized. The substituent effects on their reactivity with H2O2 and formation of quinone methide (QM) have been investigated. NMR spectroscopy and ethyl vinyl ether (EVE) trapping experiments were used to determine the reaction mechanism and QM formation, respectively. QMs were not generated during oxidative cleavage of the boronic esters but by subsequent transformation of the phenol products under physiological conditions. The oxidative deboronation is facilitated by electron-withdrawing substituents, such as aromatic F, NO2, or benzylic N(+)Me3Br(-), whereas electron-donating substituents or a better leaving group favor QM generation. Compounds containing an aromatic CH3 or OMe group, or a good leaving group (Br), efficiently generate QMs under physiological conditions. Finally, a quantitative relationship between the structure and activity has been established for the arylboronic esters by using a Hammett plot. The reactivity of the arylboronic acids/esters and the inhibition or facilitation of QM formation can now be predictably adjusted. This adjustment is important as some applications may benefit and others may be limited by QM generation.

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