Palladium-catalyzed inter- and intramolecular cross-coupling reactions of B-alkyl-9-borabicyclo[3.3.1]nonane derivatives with 1-halo-1-alkenes or haloarenes. Syntheses of functionalized alkenes, arenes, and cycloalkenes via a hydroboration-coupling sequence

Miyaura, Norio; Ishiyama, Tatsuo; Sasaki, Hironobu; Ishikawa, Masako; Sato, Makoto; Suzuki, Akira

doi:10.1021/ja00183a048

Cited by 547 publications

(215 citation statements)

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“…[44][45][46] There have been several reports of model reactions for chain-growth Suzuki-Miyaura coupling polymerization, [47][48][49] but the chain-growth condensation polymerization had not been demonstrated yet. Furthermore, in chain-growth Suzuki-Miyaura coupling polymerization, stable arylpalladium(II) halide complex could be used as an externally added initiator, and the aryl group of the complex would serve as an initiator unit of the polymer.…”

Section: Catalyst-transfer Condensation Polymerization Via Suzuki-miymentioning

confidence: 99%

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Miyakoshi

Yokoyama

Yokozawa

2007

J. Polym. Sci. A Polym. Chem.

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ABSTRACT:We describe the development of chain-growth condensation polymerization for the synthesis of well-defined p-conjugated polymers via a new polymerization mechanism, catalysttransfer polymerization. We first studied the condensation polymerization of Grignard-type hexylthiophene monomer with a Ni catalyst as a part of our research on chain-growth condensation polymerization, and found that this polymerization also proceeded in a chain-growth polymerization manner. However, the polymerization mechanism involving the Ni catalyst was different from that of previous chain-growth condensation polymerizations based on substituent effects; the Ni catalyst catalyzed the coupling reaction of the monomer with the polymer, followed by the transfer of Ni (0)

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Section: Catalyst-transfer Condensation Polymerization Via Suzuki-miymentioning

confidence: 99%

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Miyakoshi

Yokoyama

Yokozawa

2007

J. Polym. Sci. A Polym. Chem.

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“…Tr eatment of phenol 6 with an excess of mucobromic acid (7)inthe presence of aqueous sodium hydroxide led to smooth 1,4-addition-elimination with exclusive displacement of the bromide b to the masked aldehyde.Insitu reduction of the resultant aldehyde and citric acid mediated lactonization afforded butyrolactone 9 in 86 % overall yield. [14] Thev inyl bromide in 9 can be cross-coupled with protected b-amino borane derivative 8 (synthesized by addition of 9-borabicyclo[3.3.1]nonane across tert-butyl methyl(vinyl) carbamate) [15] by employing aSuzuki-Miyaura coupling.This sp 3 -sp 2 coupling [16] was particularly challenging and required extensive experimentation to discover the optimum conditions of catalytic Pd(dppf)Cl 2 ·CH 2 Cl 2 in the presence of cesium carbonate in an aqueous DMF/THF mixture at 40 8 8C. This yielded the required functionalized butenolide 5 in 58 %y ield (on ag reater than 5gscale).…”

mentioning

confidence: 99%

A Cascade Strategy Enables a Total Synthesis of (±)‐Morphine

et al. 2016

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Morphine has been at arget for synthetic chemists since Robinson proposed its correct structure in 1925, resulting in al arge number of total syntheses of morphine alkaloids. Here we report atotal synthesis of (AE)-morphine that employs two key strategic cyclizations:1 )ad iastereoselective lightmediated cyclization of an O-arylated butyrolactone to form atricyclic cis-fused benzofuran and 2) acascade ene-yne-ene ring closing metathesis to forge the tetracyclic morphine core. This approach enables as hort and stereoselective synthesis of morphine in an overall yield of 6.6 %.Morphine (1), named by Sertürner for its tendency to induce sleep,isthe most abundant alkaloid isolated from the opium poppy Papaver somniferum.[1] As the main constituent of opium, morphinesp ain relieving properties have been exploited for thousands of years,a nd in modern times have resulted in its place on the World Health Organizationslist of essential medicines.[2] Its correct structure was proposed by Robinson in 1925, [3] and was confirmed by Gates (through total synthesis,1 952) [4] and Hodgkin (using X-ray crystallography,1955).[5] Currently,all medicinal (and illicit) morphine is derived from natural sources;t here is no synthetic route that competes on scale and cost with isolation from natural sources.This problem has been elegantly outlined in arecent perspective from Hudlicky,w hich focuses on his groups chemoenzymatic approaches to the morphine skeleton, [6] and in other reviews which focus on the range of strategies employed in total syntheses of morphine alkaloids.[7] Nonetheless,t he combination of potent biological effects and ac omplex pentacyclic structure bearing five contiguous stereocentres has made morphine and its associated alkaloids an enduring challenge for synthetic chemistry,r esulting in more than 30 total or formal syntheses of morphine alkaloids. [8,9] Our proposed strategy for the total synthesis of morphine is outlined below (Scheme 1). It has been demonstrated by Fuchs that the piperidine ring in morphine (1)can be made by an intramolecular 1,6-addition of an amine analogous to that in 2.[10] This requires an a,b,g,d-unsaturated ketone,which we envisaged could be constructed via acascade ene-yne-ene ring closing metathesis from the heavily functionalized benzofuran 3. [11,12] Ametathesis cascade cyclization offers the potential for anew end-game to the total synthesis of morphine in which the requisite functional groups are installed prior to the formation of the Band Crings.This has the advantage of minimizing late-stage functional group interconversions once the ABCD tetracycle is complete. Theb enzofuran 3 could be synthesized from the tricyclic butyrolactone 4 by as eries of functional group interconversions to install the vinyl ketone and alkyne functional groups. We recognized that the cis-fused butyrolactone 4,bearing an all-carbon quaternary stereocentre,c ould be generated via ap hotocyclization from substituted butenolide 5,w ith the relative stereochemistry ac onsequence of the 5,5-c...

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“…After reduction and protection of the ketone moiety, nitrile 10 was converted to diene 11 through an addition reaction with MeLi followed by a Wittig reaction. The stereocontrolled construction of the side chain was achieved through hydroboration of diene 11 using 9-borabicyclo[3.3.1]nonane (9-BBN) followed by palladium-catalyzed coupling with vinyl bromide, 7 while the configuration of the C20 position was not confirmed until the completion of the total synthesis.…”

mentioning

confidence: 99%

Asymmetric Total Synthesis of Glycinoeclepin A: Generation of a Novel Bridgehead Anion Species

Shiina¹,

Tomata²,

Miyashita³

et al. 2010

Chemistry Letters

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The asymmetric total synthesis of glycinoeclepin A, a hatchstimulating agent of the soybean cyst nematode, was accomplished on the basis of a cyclopentene annulation for constructing the CD ring moiety having contiguous quaternary carbon atoms. Introduction of the A ring moiety was achieved by an alkylation reaction using a 7-oxabicyclo[2.2.1]hex-1-yl anion species.The soybean cyst nematode (SCN) is a devastating pest of a small group of host plants including soybean, kidney bean, and adzuki. They have a limited host range and the specificity arises from response to specific stimuli secreted by the host plant. 10¹11 g mL ¹1 ) of the SCN.2 From a synthetic point of view, the structural features of 1, namely, the contiguous quaternary carbon atoms on the CD ring system and the A ring with an oxygen bridge have attracted considerable attention from organic chemists, and three groups have reported the asymmetric total synthesis of 1. Recently, we developed a stereoselective cyclopentene annulation method for preparing a CD ring segment of steroids from enone 3 on the basis of a conjugate addition reaction using nitrile 2a (Scheme 1). 4 Thus, the reaction of enone 3 with a carbanion species, which was generated from nitrile 2a and potassium bis(trimethylsilyl)amide (KHMDS), followed by acetic anhydride afforded enol acetate 4 stereoselectively. Treatment of the adduct with aqueous hydrochloric acid resulted in formation of enone 5a via hydrolysis of the enol ether moiety and intramolecular aldol condensation. Since the method was also effective for the stereoselective synthesis of enone 5b with contiguous quaternary carbon atoms, we planned to develop a concise route for the asymmetric total synthesis of glycinoeclepin A (1) as shown in Scheme 2.We chose optically active £-silyloxy enone 7 5 as the substrate of the cyclopentene annulation. Thus, bicyclic enone 6, a monooxygenated analog of enone 5b, would be obtained through attack of the anion species of nitrile 2b on enone 7 from the opposite face of the TBSO group. The cyano group of 6 would be utilized for the stereoselective construction of the side chain through a hydroboration reaction of diene III followed by the SuzukiMiyaura coupling. With a view to introducing the A ring moiety in a straightforward manner, we planned to develop a coupling reaction of anionic species I with the CD ring segment II.The CD ring segment was synthesized as shown in Scheme 3. Enone 7 5 was treated with the anion generated from nitrile 8 6 followed by acetic anhydride to afford enol acetate 9 with high stereoselectivity (96:4). In order to avoid removal of the TBS group by hydrochloric acid, the cyclization reaction was performed by heating the crude product in aqueous acetic acid, and enone 6 was obtained in 62% yield after recrystallization. The trans relationship between the two methyl groups of enone 6 was established by NOE experiments. After reduction and protection of the ketone moiety, nitrile 10 was converted to diene 11 through an addition reaction with MeLi followed by...

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Palladium-catalyzed inter- and intramolecular cross-coupling reactions of B-alkyl-9-borabicyclo[3.3.1]nonane derivatives with 1-halo-1-alkenes or haloarenes. Syntheses of functionalized alkenes, arenes, and cycloalkenes via a hydroboration-coupling sequence

Cited by 547 publications

References 3 publications

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

A Cascade Strategy Enables a Total Synthesis of (±)‐Morphine

Asymmetric Total Synthesis of Glycinoeclepin A: Generation of a Novel Bridgehead Anion Species

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