Preparation of (<i>Z</i>)-α,β-Disubstituted Enamides via Palladium-Catalyzed Addition of Boronic Acids to Ynamides

Yang, Yongrong; Wang, Lina; Zhang, Fang; Zhu, Gangguo

doi:10.1021/jo501894j

Cited by 46 publications

(48 citation statements)

References 64 publications

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“…3 Hz,3H). 13 C NMR (acetone-d 6 ): δ = 167. 8, 143.5, 142.2, 140.1, 132.8, 132.6, 131.8, 131.2, 130.3, 129.5, 128.6, 128.0, 127.7, 70.6, 52.3, 36.1, 32.3, 25.8, 23.2, 14.2.…”

Section: Discussionmentioning

confidence: 99%

“…10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 4 In the hydroarylation of propargylamines 5 with ArB(OH) 2 , the use of palladium catalysis resulted in a complete inversion of the regioselectivity respect to rhodium catalysis; 12 a similar trend has been recently observed by Zhu & coll. 13 and Lam & coll. 14 starting from ynamides.…”

Section: Methodsmentioning

confidence: 99%

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Pd- and Rh-Catalyzed Hydroarylation of γ-(2-Methoxycarbonylphenyl)propargylic Alcohols: Approaches to 4- or 5-Substituted Seven-Membered Benzolactones and 3,3-Disubstituted Phthalides

et al. 2015

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A study of the palladium-catalyzed hydroarylation/hydrovinylation reaction of γ-(2-methoxycarbonylphenyl)propargylic alcohols with aryl iodides/vinyl triflates and of the rhodium-catalyzed one with organoboron derivatives is described. The opposite regiochemical outcome of the two processes allows an easy selective approach to 5- or 4-substituted benzoxepin-1(3H)-ones by combining the hydroarylative/hydrovinylative step with cyclocondensation between -OH and -COOMe groups in the intermediate γ,γ-disubstituted or β,γ-disubstituted allylic alcohols. A one-flask procedure to give benzo[c]oxepin-1(3H)-ones directly from the starting alkyne has been also developed. Treatment of crude γ,γ-disubstituted allylic alcohols with NaOH, followed by acidification, affords 3,3-disubstituted phthalides.

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“…3 Hz,3H). 13 C NMR (acetone-d 6 ): δ = 167. 8, 143.5, 142.2, 140.1, 132.8, 132.6, 131.8, 131.2, 130.3, 129.5, 128.6, 128.0, 127.7, 70.6, 52.3, 36.1, 32.3, 25.8, 23.2, 14.2.…”

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Pd- and Rh-Catalyzed Hydroarylation of γ-(2-Methoxycarbonylphenyl)propargylic Alcohols: Approaches to 4- or 5-Substituted Seven-Membered Benzolactones and 3,3-Disubstituted Phthalides

et al. 2015

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“…The residue obtained was washed with water and purified by crystallisation using ethanol to give pure product 1. 2,109.5,117.1,122.4,126.7,127.4,129.7,130.4,131.4,134.5,135.8,136.5,137.6,178.3;IR (KBr) NO: C,60.46;H,3.26;N,5.04. Found: C 60.61;H,3.35;N,4.88%.…”

Section: Synthesis Of (E)-2-arylmethylidene-23-dihydro-1h-pyrrolisinmentioning

confidence: 99%

Synthesis of Novel Dispiro[Acenaphthylene-Pyrrolidine-Pyrrolisine] Derivatives via a 1,3-Dipolar Cycloaddition of Azomethine Ylide

Liu

et al. 2013

Journal of Chemical Research

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1H-pyrrolisin-1-one was reacted with aromatic aldehyde to give (E)-2-arylmethylidene-2,3-dihydro-1H-pyrrolisin-1-ones. A 1,3-dipolar cycloaddition of azomethine ylide generated in situ from acenaphthenequinone and sarcosine with (E)-2-arylmethylidene-2,3-dihydro-1H-pyrrolisin-1-ones gave novel 4'-aryl-1'-methyl-1''H,2H-dispiro [acenaphthylene-1,2'pyrrolidine-3',2''-pyrrolisine]-1'',2-diones in moderate yields. The structures of all the products were characterised by NMR, IR, MS and the stereochemistry of the dispiro[acenaphthylene-pyrrolidine-pyrrolisine] derivatives was confirmed by X-ray crystallography.

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“…[12] Undoubtedly, the realizationo facomplementary regioselective method to the precedentm ethods is of considerable importance.H erein, we presento ur resultso nC u-catalyzed hydroboration of ynamides [13] with B 2 pin 2 for the effective synthesis of stereodefined (E)-b-alkenylamide boronates under mild reaction conditions. Compared with Zhu and co-workers'p rotocol, [11b] the method presented here provides ar eversed regioselectivity,w hich may significantly enhancet he scope and syntheticu sefulness of hydroboration methods.…”

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confidence: 99%

“…Thus, we decided to choose LiOtBu fort he further optimization. The use of other solvents, such as 1,4-dioxane and MeOH,w as found to be beneficial for the b-borylation, and the selectivity was further increased to > 98 % b with THF as the solvent (Table 1, entries [12][13][14]. Finally,afull completion of the reaction was achieved by carrying out the transformation at 60 8C for 5h,g iving rise to (E)-b-alkenylamide boronate 3a in 85 % yield upon isolation with excellent regioselectivity (Table 1, entry 15).…”

mentioning

confidence: 99%

Copper‐Catalyzed β‐Selective Hydroborylation of Ynamides: A Facile Access to (E)‐β‐Alkenylamide Boronates

et al. 2015

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AC u-catalyzed, highly b-selective borylation of ynamides with bis(pinacolato)diboron as the hydroboration reagent is reported, giving (E)-b-alkenylamide boronates in excellent regio-and stereoselectivity under mild reaction conditions, whichp rovides ac omplementary regioselectivity to the existing methods.Alkenylboronates are versatile synthetic intermediates and valuable reagents in organic synthesis because of their applicability toward ad iversea rray of chemical transformations, including transition-metal-catalyzedc ross-coupling reactions.[1] In this context, the hydroboration of alkynes, with or without promoters, has become one of the most straightforwarda nd efficient methods for producing these molecules. [2][3][4] It should be noted, however, that most of the previousr eports focus on the transformation of terminal acetylenes, [2][3][4] while only limited examples of the hydroboration of unsymmetrical internal alkynes have been demonstrated, [5] mainly duet ot he low reactivity or unsatisfactory regio-and stereoselectivity.A ss uch, the development of regiocontrolled hydroboration of internal alkynes still remainst ob eexplored.Besidesa cetylenic esters, [5g, h] ac lass of activated alkynes, severaln on-activated, unsymmetrical, internal acetylenes have recently emerged as effective substrates for the regioselective hydroboration reactiono wing to recentd evelopments in the Cu-catalyzed hydroboration process. For example, Ts uji and coworkers [6] developeda ne legant regiodivergenth ydroboration of 1-aryl-1-alkynes by the choice of organoboron reagents, pinacolborane (HBpin) or bis(pinacolato)diboron (B 2 pin 2 ).[7] Ar egiocontrolled hydroborationo fp ropargylic-functionalized internal alkynes was realized by Arrayµs,C arreteroa nd co-workers.[8] Meanwhile, the McQuade group reported ar egio-and stereoselective hydroboration of propargylic alcohol derivatives to yield a-o rb-borylated products by matching substrates and copper catalysts.[9] We have also accomplished aC u-catalyzed regioselective hydroboration of thioalkynesf or the divergent construction of (Z)-1-thio-and (Z)-2-thio-1-alkenyl boronates, in which the SR group plays ak ey role in determining the regioselectivity (Scheme1).[10a]On the other hand, the regiocontrolled hydroboration of ynamides constitutes as ignificant challenge because of the readilyp rotonolysiso fC ÀBb onds of the resulting alkenylamide boronates, [11a] until ar ecent report by Zhu and co-workers, [11b] in which they developed aC u-catalyzed a-selective borylationo fy namides with readily available B 2 pin 2 as the hydroborating reagent. In contrast, there is no general method for the regioselective b-borylation of ynamides.[12] Undoubtedly, the realizationo facomplementary regioselective method to the precedentm ethods is of considerable importance.H erein, we presento ur resultso nC u-catalyzed hydroboration of ynamides [13] with B 2 pin 2 for the effective synthesis of stereodefined (E)-b-alkenylamide boronates under mild reaction conditions. Compared ...

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Preparation of (Z)-α,β-Disubstituted Enamides via Palladium-Catalyzed Addition of Boronic Acids to Ynamides

Cited by 46 publications

References 64 publications

Pd- and Rh-Catalyzed Hydroarylation of γ-(2-Methoxycarbonylphenyl)propargylic Alcohols: Approaches to 4- or 5-Substituted Seven-Membered Benzolactones and 3,3-Disubstituted Phthalides

Pd- and Rh-Catalyzed Hydroarylation of γ-(2-Methoxycarbonylphenyl)propargylic Alcohols: Approaches to 4- or 5-Substituted Seven-Membered Benzolactones and 3,3-Disubstituted Phthalides

Synthesis of Novel Dispiro[Acenaphthylene-Pyrrolidine-Pyrrolisine] Derivatives via a 1,3-Dipolar Cycloaddition of Azomethine Ylide

Copper‐Catalyzed β‐Selective Hydroborylation of Ynamides: A Facile Access to (E)‐β‐Alkenylamide Boronates

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