Geminal Difunctionalization of Alkenylidene-Type Carbenoids by Using Interelement Compounds

Hata, Toshiyuki; Kitagawa, Hirotoshi; Masai, Hirokazu; Kurahashi, Takuya; Shimizu, Masaki; Hiyama, Tamejiro

doi:10.1002/1521-3773(20010216)40:4<790::aid-anie7900>3.0.co;2-t

Cited by 170 publications

(19 citation statements)

References 52 publications

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“…1,1‐Diborylalkenes can be made from either 1,1‐dichloro‐ or 1,1‐dibromoalkenes through lithium–halide exchange and subsequent reaction with bis(pinacolato)diboron (B 2 pin 2 ; Figure 1 a). 7, 8 Alternatively, they can be accessed by hydroboration of alkynylboronates,9 or by dehydrogenative borylation of alkenes with diboron reagents 10. Metal‐catalyzed addition of diboron reagents to terminal or internal alkynes leads to 1,2‐ cis ‐diborylalkenes (Figure 1 b).…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Triborylalkenes from Terminal Alkynes by Iridium‐Catalyzed Tandem CH Borylation and Diboration

et al. 2015

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Atwo-step reaction to convert terminal alkynes into triborylalkenes is reported. In the first step,the terminal alkyne and pinacolborane (HBpin) are converted into an alkynylboronate,which is catalyzedbyaniridium complex supported by aS iNN pincer ligand. In the second step,t reatment of the reaction mixture with CO generates an ew catalyst which mediates dehydrogenative diboration of alkynylboronate with pinacolborane.T he mechanism of the diboration remains unclear but it does not proceed via intermediacy of hydroboration products or via B 2 pin 2 .

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Section: Methodsmentioning

confidence: 99%

Synthesis of Triborylalkenes from Terminal Alkynes by Iridium‐Catalyzed Tandem CH Borylation and Diboration

et al. 2015

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“…Treatment of 1-bromo-1-lithioethene (1 mol), generated from vinyl bromide and lithium 2,2,6,6-tetramethylpiperi- 2). In view that diboron 1 reacts with an equimolar amount of 1bromo-1-lithioethene to give 2a in 91% yield, 3 the low yield indicates that the reaction of the carbenoid with 2a is slower than with 1 and apparently competes with the decomposition of the lithium carbenoid. Then, we increased the amount of the carbenoid reagent, and observed that 72% yield was achieved when 5 molar equivalents of vinyl bromide and LiTMP were employed as shown in Scheme 2.…”

Section: Equationmentioning

confidence: 99%

“…Very recently, we found that treatment of bis(pinacolato)diboron 1 or (dimethylphenylsilyl)(pinacolato)boron 3 with 1-halo-1-alkenyllithium gave the corresponding 1,1-bisborylalkenes 2 or 1-silyl-1-borylalkenes 4, respectively. 3 In particular, 2 is a parent example of bis(alkenylboron) compounds (eq. ).…”

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confidence: 99%

Novel Synthesis of 2,3-Bisboryl-1,3-dienes from 1-Bromo-1-lithioethene and 1,1-Bisborylalkenes

Shimizu¹,

Kurahashi²,

Hiyama³

2001

Synlett

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Treatment of 1,1-[bis(pinacolato)boryl]alkenes with excess of 1-bromo-1-lithioethene was found to give 2,3-bis[(pinacola-to)boryl]-1,3-dienes in moderate to good yields. Synthetic applications of 2,3-[bis(pinacolato)boryl]-1,3-butadiene were also demonstrated. Alkenylboron compounds are readily accessible and extremely useful reagents in organic synthesis. 1 In contrast, bis(alkenylboron) compounds have attracted less attention probably because their facile syntheses are quite limited , 2 though bis(alkenylboron) compounds would be employed for an efficient synthesis of polysubstituted ole-fins through double carbon-carbon bond formation with retention of configuration by a simple experimental operation. Very recently, we found that treatment of bis(pina-colato)diboron 1 or (dimethylphenylsilyl)(pinacolato)-boron 3 with 1-halo-1-alkenyllithium gave the corresponding 1,1-bisborylalkenes 2 or 1-silyl-1-borylalkenes 4, respectively. 3 In particular, 2 is a parent example of bis(alkenylboron) compounds (eq.). Equation During the course of the synthetic studies, we eventually found that 2,3-bisboryl-1,3-dienes 5a were produced when excess of 1-bromo-1-lithioethene was treated with 1. Formation of 5a was ascribed to the reaction of 1,1-bis-borylethene 2a with CH 2 =CBrLi followed by 1,2-migration of a carbon (Scheme 1). 1 We report herein that the synthesis of 2,3-bisboryl-1,3-dienes is general, 4 and bis-borylated 1,3-dienes 5 serve as useful precursors of complex 1,3-dienes. 5 In addition, introduction of two boryl groups into a 1,3-diene unit enhances the synthetic utility of the addition products. Scheme 1 B = B(OCMe 2) 2 Treatment of 1-bromo-1-lithioethene (1 mol), generated from vinyl bromide and lithium 2,2,6,6-tetramethylpiperi-dide (LiTMP) in THF-Et 2 O (2:1) at-110 °C, with 1,1-bis[(pinacolato)boryl]ethene 2a (1 mol) at-110 °C gave 2,3-bisboryl-1,3-butadiene 5a in 7% yield (Scheme 2). In view that diboron 1 reacts with an equimolar amount of 1-bromo-1-lithioethene to give 2a in 91% yield, 3 the low yield indicates that the reaction of the carbenoid with 2a is slower than with 1 and apparently competes with the decomposition of the lithium carbenoid. Then, we increased the amount of the carbenoid reagent, and observed that 72% yield was achieved when 5 molar equivalents of vinyl bromide and LiTMP were employed as shown in Scheme 2. 6,7 Noteworthy is that 5a can be purified by column chromatography on silica gel since 2-boryl-1,3-diene is reported to be highly susceptible to dimerization. 8 Car-benoid generation carried out in the presence of 2a gave 5a in lower yield (59%), while reaction of 2-substituted 1-bromo-1-lithioethene with 2a did not proceed at all. Scheme 2 Synthesis of 2,3-bisboryl-1,3-diene 5a The optimized conditions were applied to 2-monosubsti-tuted bisborylethenes 2b and 2c. The corresponding conjugated triene 5b as a E/Z mixture (73:27) and dienyne 5c as the only E-isomer were respectively isolated in 74% and 38% yields. 9 The stereochemical outcome indicates that 1-bromo-1-lithioethene pref...

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“…The addition of interelement compounds with heteroatom-heteroatom single bonds to carbon-carbon unsaturated bonds has recently attracted wide attention as an atomically efficient method for carbon-heteroatom bond formation [1][2][3][4][5][6]. This addition reaction is promoted by transition-metal catalysts, acids, bases, and radical initiators [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Photoinduced Bisphosphination of Alkynes with Phosphorus Interelement Compounds and Its Application to Double-Bond Isomerization

et al. 2022

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The addition of interelement compounds with heteroatom-heteroatom single bonds to carbon-carbon unsaturated bonds under light irradiation is believed to be an atomically efficient method to procure materials with carbon-heteroatom bonds. In this study, we achieved the photoinduced bisphosphination of alkynes using the phosphorus interelement compound, tetraphenyldiphosphine monosulfide (1), to stereoselectively obtain the corresponding (E)-vic-1,2-bisphosphinoalkenes, which are important transition-metal ligands. The bisphosphination reaction was performed by mixing 1 and various alkynes and then exposing the mixture to light irradiation. Optimization of the conditions for the bisphosphination reaction resulted in a wide substrate range and excellent trans-selectivity. Moreover, the completely regioselective introduction of pentavalent and trivalent phosphorus groups to the terminal and internal positions of the alkynes, respectively, was achieved. We also found that the novel double-bond isomerization reaction of the synthesized bisphosphinated products occurred with a catalytic amount of a base under mild conditions. Our method for the photoinduced bisphosphination of carbon-carbon unsaturated compounds may have strong implications for both organic synthesis and organometallic and catalyst chemistry.

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Geminal Difunctionalization of Alkenylidene-Type Carbenoids by Using Interelement Compounds

Abstract: A 1,2‐migration of a boryl or silyl group with inversion of configuration occurs in the reaction of alkylidene‐type lithium carbenoids with diboron or silylborane derivatives to give the corresponding 1,1‐diboryl‐ or 1‐boryl‐1‐silylalkenes in good yields (see scheme).

Cited by 170 publications

References 52 publications

Synthesis of Triborylalkenes from Terminal Alkynes by Iridium‐Catalyzed Tandem CH Borylation and Diboration

Synthesis of Triborylalkenes from Terminal Alkynes by Iridium‐Catalyzed Tandem CH Borylation and Diboration

Novel Synthesis of 2,3-Bisboryl-1,3-dienes from 1-Bromo-1-lithioethene and 1,1-Bisborylalkenes

Photoinduced Bisphosphination of Alkynes with Phosphorus Interelement Compounds and Its Application to Double-Bond Isomerization

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