Hydroboration. XI. The Hydroboration of Acetylenes—A Convenient Conversion of Internal Acetylenes into cis-Olefins and of Terminal Acetylenes into Aldehydes

Brown, Herbert C.; Zweifel, George

doi:10.1021/ja01479a024

Cited by 201 publications

(52 citation statements)

References 1 publication

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“…We make this observation because for this particular reduction a possible explanation is available. In the solution reaction the vinyl borane intermediate, hydrolyzed by protonolysis with acetic acid, yields boron-containing impurities which must be removed by treatment with hydrogen peroxide (15). In the analogous reductions of 19 and 21 leading to 25 and 26, the boroncontaining impurities are removed by simple filtration, as the desired products are bound to the insoluble support, and the products 27 and 28 are thus not subjected to treatment with hydrogen peroxide.…”

Section: Resultsmentioning

confidence: 99%

The use of polymer supports in organic synthesis. XII. The total stereoselective synthesis of cis insect sex attractants on solid phases

Fyles¹,

Leznoff²,

Weatherston³

1977

Can. J. Chem.

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. Can. J. Chem. 55,4135 (1977).A 2% crosslinked divinylbenzene-styrene copolymer, incorporating trityl chloride groups (2) was used in the synthesis of insect sex attractants of Lepidoptera by a two-step alkyne coupling route. Polymer 2 reacted with the symmetrical diols, 1,s-octanediol and 1, lO-decanediol, to give the monoblocked polymer-bound diols 5 and 6 respectively. Mesylation of 5 and 6 gave the polymer-bound monomesylates 7 and 8 which on coupling with lithioacetylide gave the polymer-bound terminal alkynes 9 and 10 respectively. Acid cleavage of 9 and 10 provide 9-decyn-1-01 and 11-dodecyn-1-01 respectively. A second coupling step was performed by lithiation of 9 and 10 with n-butyllithium or tert-butyllithium followed by treatment with n-butyl bromide or ethyl bromide to give polymer-bound internal alkynes, which on acid hydrolysis gave 9-tetradecyn-1-01 (22), 11-hexadecyn-1-01 (23), and 11-tetradecyn-1-ol(24). If 10 had been lithiated with n-butyllithium and coupled with ethyl bromide, some translithiation occurred to liberate n-butyl bromide which entered into the coupling reaction eventually giving a mixture of 23 and 24. This problem was resolved by the use of tert-butyllithium in the lithiation step. Attempts were made to reduce polymer-bound internal alkynes stereoselectively to cis-alkenes with 9-borabicyclononane, diisobutylaluminum hydride, and catechol borane but all these reagents proved inadequate due to incomplete reduction, overreduction, hydrogenolysis of the alkyne from the polymer, and non-selectivity. Polymer-bound internal alkynes were quantitatively reduced exclusively to cis insect sex attractants using disiamylborane without concurrent overreduction or hydrogenolysis. THOMAS M. FYLES, CLIFFORD C. LEZNOFF et JOHN WEATHERSTON. Can. J. Chem. 55,4135 (1977).On a utilist un copolymere divinylbenzkne-styrkne rCticul.4 a 2% et incorporant des groupes chlorure de trityle (2) pour rCaliser la synthtse de l'attirant sexuel du Lepidoptera en faisant appel a un schtma de couplage d'alcynes impliquant deux Ctapes. I,e polymtre 2 rCagit avec les diols symCtriques octanediol-1,s et dtcanediol-l,l0 pour conduire suivant le cas aux diols monobloquCs 5 et 6 liCs au polymtre. La mksylation de 5 et 6 fournit les monomCsylates 7 et 8 lies au polymere qui, par couplage avec I'acCtylure de lithium, conduisent respectivement aux alcynes terminales 9 et 10 liCs au polymtre. Une scission acide de 9 et 10 conduit respectivement aux dCcyn-9 01-1 et dodCcyn-11 01-1. Une nouvelle Ctape de couplage, effectute par la lithiation I de 9 et 10 avec le n-butyllithium ou le tert-butyllithium, suivie par un traitement avec le bromure de n-butyle ou le bromure d'Cthyle conduit aux alcynes internes liCs au polymtre qui par hydrolyse acide fournissent le tCtradCcyn-9 01-1 (22), I'hexadCcyn-11 01-1 (23) et le tCtradCcyn-11 01-1 (24). Si l'on avait effectuk la lithiation de 10 avec du n-butyllithium et si on I'avait couplC avec du bromure d7Cthyle, il se serait produit un peu de translithiation pour IibCrer du bromur...

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Section: Resultsmentioning

confidence: 99%

The use of polymer supports in organic synthesis. XII. The total stereoselective synthesis of cis insect sex attractants on solid phases

Fyles¹,

Leznoff²,

Weatherston³

1977

Can. J. Chem.

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“…The resulting solid residue was recrystallized from MeCN to give 4 a (3.34 g, 15.38 mmol, 77 % yield) as colorless needles. ; IR (KBr): ñ = 3000 (br), 1622,1598,1573,1494,1469,1454,1277,1242,1206 4,136.1,135.1 (br),128.4,126.5,125.7,62.5,50.4 ppm;MS (EI): m/z (%): 217 (M + , 1), 187 (9), 186 (100), 185 (8), 130 (7), 129 (9), 114 (87), 103 (25), 77 (15); elemental analysis calcd for C 12 H 16 BNO 2 : C 66.40,H 7.43,N 6.45;found: C 66.36,H 7.35,N 6.45.…”

Section: Methodsmentioning

confidence: 99%

“…[26] The generally high hydroboration regioselectivities of iPP 2 BH compare favorably with those observed for CthBH [18] and Hal 2 BH·Me 2 S, [19] the commonly used reagents to produce the corresponding boronic acids under hydrolytic, nonoxidative conditions (Figure 2). The similar selectivities achieved with iPP 2 BH (1) and Sia 2 BH [2,15] may be attributed to their comparable steric demand (see Scheme 2).…”

mentioning

confidence: 95%

“…Of particular interest, 1:1 hydroboration of 2,5-dimethylhexa-2,4-diene (2, Scheme 3) with 9-BBN leads to the anti-Markovnikov monohydroboration product in 90 % yield. [14] Based on these studies, we postulated that the reaction of borane with slightly more than 2 equivalents of 2 would mainly lead, by double antiMarkovnikov hydroboration, to 1, which was expected to exhibit hydroboration selectivity resembling that of disiamylborane, [2,15] reactivity towards carbonyls similar to that of allyl boranes, [3,16] and facile hydrolysis in protic media [17] (Scheme 2). Consequently, we envisaged that 1 could serve as a valuable hydroboration reagent, allowing conversion of the product boranes into the corresponding boronic acids under mild conditions similar to those used for the hydrolysis of catechol- [18] and dihaloboranes, [19] without the need for the standard strong oxidizing reagents.…”

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confidence: 99%

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Di(isopropylprenyl)borane: A New Hydroboration Reagent for the Synthesis of Alkyl and Alkenyl Boronic Acids

2003

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The best of the old: The new hydroboration reagent 1 combines the selectivity of disiamylborane (2) with the reactivity towards carbonyls of allyl boranes 3. Conventional oxidative workup conditions are avoided, as facile hydrolysis in protic media provides the corresponding boronic acids with up to 99 % anti‐Markovnikov selectivities. A one‐pot hydroboration/Suzuki–Miyaura protocol adds to the synthetic value of 1.

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“…98 %) Synthesen unsymmetrisch substituierter konjugierter (E, E)-und (E, Z)-Diene führten (Schema 2). [12] Diese Forschungen knüpften an die wegweisenden Untersuchungen zur Alkinhydroborierung durch Brown [13] und zur C-C-Verknüpfung durch Zweifel [14] an.…”

Section: Negishi-kupplungunclassified

Die magische Kraft der Übergangsmetalle: Vergangenheit, Gegenwart und Zukunft (Nobel‐Aufsatz)

Negishi

2011

Angewandte Chemie

183

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In meinem ersten Jahr an der Shonan errang damit den 123. Platz der schulischen Leistung unter etwas mehr als 400 Mitschülern. Nach einem kurzen Augenblick der Enttäu-schung erkannte ich, dass zwar etwas mehr als 100 Schüler vor mir lagen, aber auch fast 300 hinter mir. Damals wurden jährlich etwa 30-40 Schüler von Shonan einschließlich der einmaligen Wiederholer an der Universität Tokio aufgenommen. Mir wurde dann plötzlich klar, dass ich sogar eine berechtigte Chance hätte, an die bis dahin für mich unerreichbar scheinende Universität Tokio zu kommen, wenn ich so hart wie möglich lernte.

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Hydroboration. XI. The Hydroboration of Acetylenes—A Convenient Conversion of Internal Acetylenes into cis-Olefins and of Terminal Acetylenes into Aldehydes

Cited by 201 publications

References 1 publication

The use of polymer supports in organic synthesis. XII. The total stereoselective synthesis of cis insect sex attractants on solid phases

The use of polymer supports in organic synthesis. XII. The total stereoselective synthesis of cis insect sex attractants on solid phases

Di(isopropylprenyl)borane: A New Hydroboration Reagent for the Synthesis of Alkyl and Alkenyl Boronic Acids

Die magische Kraft der Übergangsmetalle: Vergangenheit, Gegenwart und Zukunft (Nobel‐Aufsatz)

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