Amine-Catalyzed Direct Aldol Addition

Markert, Morris; Mulzer, Michael; Schetter, B.; Mahrwald, Rainer

doi:10.1021/ja071926a

Cited by 90 publications

(46 citation statements)

References 25 publications

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“…The corresponding anti-configured product was not detected. These observations are consistent with results we obtained in amine catalyzed direct aldol additions with dihydroxyacetone [66,67]. Further extension of this observation to other pentoses yields the corresponding Knoevenagel-addition adducts albeit with lower yields.…”

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confidence: 92%

Organocatalyzed Cascade Reaction in Carbohydrate Chemistry

Mahrwald

2015

SpringerBriefs in Molecular Science

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The extensive and extremely strong development of organocatalysis over the last years provided versatile methodologies for convenient utilization of the carbonyl function of unprotected carbohydrates in C-C-bond formation processes. These biomimetic amine-activated mechanisms enable multiple cascade-protocols for the synthesis of a large scope of carbohydrate derived compound classes. Several, only slightly different protocols have been developed for the application of 1.3-dicarbonyls in stereoselective chain-elongation of unprotected carbohydrates and the synthesis of highly functionalized C-glycosides of defined configuration. Furthermore, the latter class of compounds can also be accessed by the use of methyl ketones. So a high substrate scope is available for the installation of desired functionalities in C-glycosides. By a one-pot, operationally simple cascade reaction of isocyanides with unprotected aldoses and amino acids an access to a broad range of defined glycosylated pseudopeptides is given. The elaborated organocatalyzed cascade-reactions provide defined access to highly functionalized carbohydrate derivatives. Depending on the reaction conditions different origin to control the installation of configuration during the bond-formation process were observed. The demonstrated organocatalyzed cascade sequences indicate the great potential of unprotected carbohydrates in the synthesis of highly functionalized bio-mimetic structure motifs by operationally simple, one-pot protocols.Due to the great biological importance of carbon chain elongated carbohydrates, the synthesis of this structural diverse compound class has attracted high synthetic interest from the scientific community. Among the elongated carbohydrates, C-Glycosides have gained considerable importance over the last few decades, since they are configuratively stable under enzymatic conditions and less prone to cleavage at the anomeric carbon. As such they are appealing substrates for chemical biology and medicinal chemistry.

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confidence: 92%

Organocatalyzed Cascade Reaction in Carbohydrate Chemistry

Mahrwald

2015

SpringerBriefs in Molecular Science

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“…To our knowledge, there has been no such report. [5][6][7] Nevertheless, the enolate mechanism does have certain advantages, especially when the formation of an enamine is difficult. During our study of using activated ketone compounds as the enamine acceptors for organocatalyzed aldol reactions, [8] we envisioned that such an organocatalyzed enolate-mediated aldol reaction should be possible if the enolate acceptor is sufficiently activated, because the equilibrium favors the formation of the product with such a substrate.…”

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confidence: 99%

Quinidine Thiourea‐Catalyzed Aldol Reaction of Unactivated Ketones: Highly Enantioselective Synthesis of 3‐Alkyl‐3‐hydroxyindolin‐2‐ones

2010

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“…The development of a syn-selective tertiary amine-catalysed direct aldol reaction has been reported by Mahrwald (Scheme 12) 23 and is complementary to the anti-selectivity generally observed for the proline-mediated process, for example the asymmetric synthesis of ulsonic acid precursors by Enders and Gasperi (Scheme 13). 24 The syntheses of L-rhamnulofuranose and 6-deoxy-L-sorbose have both been reported using Mahrwald's method (see section 8.0).…”

Section: Scheme 11mentioning

confidence: 88%