Recent Advances in the Baylis−Hillman Reaction and Applications

Basavaiah, Deevi; Rao, and Anumolu Jaganmohan; Satyanarayana, T.

doi:10.1021/cr010043d

Cited by 1,591 publications

(578 citation statements)

References 481 publications

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“…[13] These pK aH values do not rationalize the observation that DMAP (1 f) and phosphanes, but not the unsubstituted pyridine 1 b, are efficient catalysts for BaylisHillman and related reactions. [25] Our finding that the wellknown organocatalyst DMAP (1 f) and triarylphosphanes or trialkylphosphanes have comparable nucleophilicity parameters N, and even more important, comparable carbon basicities [26] (Scheme 5) suggests to employ these quantities for the systematic analysis of nucleophilic organocatalysts.…”

Section: Resultsmentioning

confidence: 99%

Nucleophilicities and Carbon Basicities of Pyridines

Brotzel

Kempf

Singer

et al. 2006

Chemistry A European J

136

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Rate and equilibrium constants for the reactions of pyridines with donor‐substituted benzhydrylium ions have been determined spectrophotometrically. The correlation equation log k(20 °C)=s(N+E), in which s and N are nucleophile‐specific parameters and E is an electrophile‐specific parameter, has been used to determine the nucleophilicity parameters of various pyridines in CH2Cl2 and aqueous solution and to compare them with N of other nucleophiles. It is found that the nucleophilic organocatalyst 4‐(dimethylamino)pyridine (DMAP) and tertiary phosphanes have comparable nucleophilicities and carbon basicities despite widely differing Brønsted basicities. For that reason, these reactivity parameters are suggested as guidelines for the development of novel organocatalysts. The Marcus equation is employed for the determination of the intrinsic barriers of these reactions.

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Section: Resultsmentioning

confidence: 99%

Nucleophilicities and Carbon Basicities of Pyridines

Brotzel

Kempf

Singer

et al. 2006

Chemistry A European J

136

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“…[1][2][3]8 Despite the impressive development of various protocols for the enantioselective azaMBH reaction involving either chiral Lewis bases or combinations of achiral Lewis bases with chiral protic co-catalysts, [4][5][6][7] the effective transformation of sterically and/or electronically deactivated Michael acceptors still provides an ambitious challenge.…”

Section: Introductionmentioning

confidence: 99%

The aza-Morita–Baylis–Hillman reaction of electronically and sterically deactivated substrates

Lindner¹,

Tandon²,

Liu³

et al. 2012

Org. Biomol. Chem.

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The aza-Morita-Baylis-Hillman (azaMBH) reaction has been studied for electronically and sterically deactivated Michael acceptors. It is found that electronically deactivated systems can be converted with electron-rich phosphanes and pyridines as catalysts equally well. For sterically deactivated systems clearly better catalytic turnover can be achieved with pyridine catalysts. This is in accordance with the calculated affinities of the catalysts towards different Michael-acceptors.

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“…14 In contrast, the Baylis-Hillman reaction was discovered in 1972. 12 Intramolecular versions of the Baylis-Hillman reaction have only recently gained favor, 13 where elegant work in this area has elevated the status of the intramolecular variant. 15 Although the Michael accepting ability of vinyl sulfones is well-documented, 16 their vinyl sulfonamide counterparts have assumed a far less prominent role as viable Michael acceptors.…”

mentioning

confidence: 99%

Synthesis of Sultam Scaffolds via Intramolecular Oxa-Michael and Diastereoselective Baylis−Hillman Reactions

Zhou

Hanson

2008

Org. Lett.

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A divergent synthetic approach to new sultams utilizing intramolecular oxa-Michael and BaylisHillman reactions of readily prepared vinyl sulfonamides and suitably protected amino alcohols, is reported. A variety of seven-and eight-membered ring sultam scaffolds were synthesized using oxaMichael pathways, whereas both five-and six-membered rings were synthesized using BaylisHillman methods. Baylis-Hillman reactions proceed with good to excellent levels of diastereoselectivity, and oxa-Michael reactions leading to eight-membered ring sultams provide empirical evidence validating 8-endo-trig cyclization pathways.Sulfonamides and their analogs have a rich chemical and biological history and have emerged as a promising class of compounds in drug discovery. 1 Sultams (cyclic sulfonamides), although not found in nature, have also shown potent biological activity, including several displaying a wide spectrum of activities. 2 The more prominent include the antiepileptic agent Sulthiame 3 (Figure 1), Brinzolamide 4 for the treatment of glaucoma, the COX-2 inhibitors Ampiroxicam 5 and S-2474, 6 and selective inhibitors of cysteine proteases involved in the progression of malaria. 7 In addition, a number of benzodithiazine dioxides and benzoxathiazepine 1,1-dioxides displaying anti-HIV-1 activity 8 and the ability to activate glucokinase 9 (type II diabetes), respectively, have been uncovered.Traditionally, sultam syntheses have relied on classical cyclization protocols and a number of transition-metal-catalyzed processes that have recently been reported. 10 Interest in the generation of new sultams for biological screening has provided impetus for exploring the Michael-accepting ability of vinyl sulfonamides. In particular, we aimed to study the titled The titled route began with the assembly of TBS-protected amino alcohols, which represent cheap and versatile building blocks for sultam scaffold synthesis. These TBS-protected alcohols were reacted with 2-chloroethanesulfonyl chloride to produce vinyl sulfonamides 2 in good yields (Scheme 1). Subsequent benzylation/allylation reactions of vinyl sulfonamides 2 yielded vinyl sulfonamides 3 in good yields over three steps. The intramolecular oxa-Michael reaction was initiated by TBS-deprotection with TBAF in THF to afford the unique seven-and eight-membered ring sultams, respectively, in excellent yield under mild condition.Several examples of this straighforward procedure were examined as outlined in Table 1. In all cases the cyclization proceeded without incident. In several cases, the entire linear sequence could be run without the need for chromatography, ultimately resulting in the production of oxathiazepine-and oxathiazocine-dioxides, seven-and eight-membered ring systems, in excellent yields, respectively. To the best of our knowledge, this work represents the first report of using intramolecular oxa-Michael reactions to generate an eight-membered ring and enriches Baldwin's rules for ring closure. 18 An orthogonal pathway leading to an intramolecular Baylis-H...

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Recent Advances in the Baylis−Hillman Reaction and Applications

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 1,591 publications

References 481 publications

Nucleophilicities and Carbon Basicities of Pyridines

Nucleophilicities and Carbon Basicities of Pyridines

The aza-Morita–Baylis–Hillman reaction of electronically and sterically deactivated substrates

Synthesis of Sultam Scaffolds via Intramolecular Oxa-Michael and Diastereoselective Baylis−Hillman Reactions

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