Solid Acids as Heterogeneous Support for Primary Amino Acid‐Derived Diamines in Direct Asymmetric Aldol Reactions

Demuynck, Anneleen L. W.; Peng, Li; Clippel, Filip de; Vanderleyden, Jozef; Jacobs, Pierre; Sels, Bert F.

doi:10.1002/adsc.201000871

Cited by 45 publications

(28 citation statements)

References 59 publications

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“…To give a partial solution, significant advances have been reported in recent times describing polymer supported organic catalysts, easily recovered after the reaction has taken place by filtration [154–156]. In contrast with immobilised metal complexes (via solid-supported bound ligand), leaching problems are much less critical when using organocatalysts immobilised by covalent bonding to the solid support.…”

Section: Discussionmentioning

confidence: 99%

Asymmetric Organocatalysis at the Service of Medicinal Chemistry

Ricci

2014

ISRN Organic Chemistry

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The application of the most representative and up-to-date examples of homogeneous asymmetric organocatalysis to the synthesis of molecules of interest in medicinal chemistry is reported. The use of different types of organocatalysts operative via noncovalent and covalent interactions is critically reviewed and the possibility of running some of these reactions on large or industrial scale is described. A comparison between the organo- and metal-catalysed methodologies is offered in several cases, thus highlighting the merits and drawbacks of these two complementary approaches to the obtainment of very popular on market drugs or of related key scaffolds.

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Section: Discussionmentioning

confidence: 99%

Asymmetric Organocatalysis at the Service of Medicinal Chemistry

Ricci

2014

ISRN Organic Chemistry

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“…In the SIMOMM QM/MM calculation, the MSN surface model is divided into the reactive site model (RSM) that is treated using QM methods, and a chemically inactive part, treated by the Tinker molecular mechanics (MM) force field. The RSM region was chosen in such a way that it contains the two major oxygen species found on the silica mesoporous surface, the silanol groups and siloxane bridges, 38,39 using the notation for silicon sites, ((HO)Si(OSi) 3 ) and ((SiO) 4 Si), respectively. The distance between hydroxyl groups should be ∼5−6 Å, in order to match the silica material characterized in the study conducted by Kandel et al 21 The 3-aminopropyl is bonded to the Si atom in a symmetric position of the RSM, Figure 1a.…”

Section: Computational Detailsmentioning

confidence: 99%

Silanol-Assisted Carbinolamine Formation in an Amine-Functionalized Mesoporous Silica Surface: Theoretical Investigation by Fragmentation Methods

et al. 2015

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The aldol reaction catalyzed by an amine-substituted mesoporous silica nanoparticle (amine-MSN) surface was investigated using a large molecular cluster model (Si392O958C6NH361) combined with the surface integrated molecular orbital/molecular mechanics (SIMOMM) and fragment molecular orbital (FMO) methods. Three distinct pathways for the carbinolamine formation, the first step of the amine-catalyzed aldol reaction, are proposed and investigated in order to elucidate the role of the silanol environment on the catalytic capability of the amine-MSN material. The computational study reveals that the most likely mechanism involves the silanol groups actively participating in the reaction, forming and breaking covalent bonds in the carbinolamine step. Therefore, the active participation of MSN silanol groups in the reaction mechanism leads to a significant reduction in the overall energy barrier for the carbinolamine formation. In addition, a comparison between the findings using a minimal cluster model and the Si392O958C6NH361 cluster suggests that the use of larger models is important when heterogeneous catalysis problems are the target. ABSTRACT: The aldol reaction catalyzed by an amine-substituted mesoporous silica nanoparticle (amine-MSN) surface was investigated using a large molecular cluster model (Si 392 O 958 C 6 NH 361 ) combined with the surface integrated molecular orbital/molecular mechanics (SIMOMM) and fragment molecular orbital (FMO) methods. Three distinct pathways for the carbinolamine formation, the first step of the amine-catalyzed aldol reaction, are proposed and investigated in order to elucidate the role of the silanol environment on the catalytic capability of the amine-MSN material. The computational study reveals that the most likely mechanism involves the silanol groups actively participating in the reaction, forming and breaking covalent bonds in the carbinolamine step. Therefore, the active participation of MSN silanol groups in the reaction mechanism leads to a significant reduction in the overall energy barrier for the carbinolamine formation. In addition, a comparison between the findings using a minimal cluster model and the Si 392 O 958 C 6 NH 361 cluster suggests that the use of larger models is important when heterogeneous catalysis problems are the target.

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“…The catalyst 480 can be recovered by filtration and reused for at least four cycles with no loss of stereoselectivity (entries 5 and 6). 276,277 Clays are abundant and available substances that promote a variety of chemical reactions. The characteristic layered structure of clays attracted the attention of synthetic chemists who have used it as a support material.…”

Section: Noncovalently Supported Organocatalystsmentioning

confidence: 99%