Chiral Brønsted Acids for Asymmetric Organocatalysis

Kampen, Daniela; Reisinger, Corinna M.; List, Benjamin

doi:10.1007/978-3-642-02815-1_1

Cited by 100 publications

(34 citation statements)

References 94 publications

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“…A subsequent nucleophilic addition to silicon removes the acetal directing groups and provides unmasked phenol products 9 in a single vessel. Importantly, the resulting ortho -silyl phenols 9 are useful synthetic vehicles for direct applications to many other important transformations, examples of which include harnessing aryne chemistry, 23 Au-catalyzed oxidative cross-coupling, 4d,e synthesis of dibenzosiloles, 24 and catalytic synthesis of a chiral BINOL 25 scaffold.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Reductive ortho-C–H Silylation of Phenols with Traceless, Versatile Acetal Directing Groups and Synthetic Applications of Dioxasilines

et al. 2016

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A new, highly selective, bond functionalization strategy, achieved via relay of two transition metal catalysts and the use of traceless acetal directing groups, has been employed to provide facile formation of C–Si bonds and concomitant functionalization of a silicon group in a single vessel. Specifically, this approach involves the relay of Ir-catalyzed hydrosilylation of inexpensive and readily available phenyl acetates, exploiting disubstituted silyl synthons to afford silyl acetals and Rh-catalyzed ortho-C–H silylation to provide dioxasilines. A subsequent nucleophilic addition to silicon removes the acetal directing groups and directly provides unmasked phenol products and, thus, useful functional groups at silicon achieved in a single vessel. This traceless acetal directing group strategy for catalytic ortho-C–H silylation of phenols was also successfully applied to preparation of multisubstituted arenes. Remarkably, a new formal α-chloroacetyl directing group has been developed that allows catalytic reductive C–H silylation of sterically hindered phenols. In particular, this new method permits access to highly versatile and nicely differentiated 1,2,3-trisubstituted arenes that are difficult to access by other catalytic routes. In addition, the resulting dioxasilines can serve as chromatographically stable halosilane equivalents, which allow not only removal of acetal directing groups but also introduce useful functional groups leading to silicon-bridged biaryls. We demonstrated that this catalytic C–H bond silylation strategy has powerful synthetic potential by creating direct applications of dioxasilines to other important transformations, examples of which include aryne chemistry, Au-catalyzed direct arylation, sequential orthogonal cross-couplings, and late-stage silylation of phenolic bioactive molecules and BINOL scaffolds.

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Section: Introductionmentioning

confidence: 99%

Catalytic Reductive ortho-C–H Silylation of Phenols with Traceless, Versatile Acetal Directing Groups and Synthetic Applications of Dioxasilines

et al. 2016

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“…All hexT conjugates were characterized; if necessary, purified to ensure fidelity; recorded by DNA ligation; and diversified by amide coupling to yield a 14.496-membered tiDEL (oligothymidine-initiated DNA-encoded library) for drug screening. Our TiDEC strategy holds promise to make several catalytic strategies 11,12 available for DNA-recorded libraries, and thereby expand their chemical space. It is likely compatible with other DEL formats that are successfully used in drug research, too.…”

Section: Discussionmentioning

confidence: 99%

“…1,4 Prolific sources of drug-like structures are Brønsted acid-, and coinage metal-catalyzed reactions. 11,12 Yet, they cause depurination, 13,14 and thus require the chemically much more stable PNA for encoding. 1c,15 …”

Section: Introductionmentioning

confidence: 99%

Acid- and Au(i)-mediated synthesis of hexathymidine-DNA-heterocycle chimeras, an efficient entry to DNA-encoded libraries inspired by drug structures

et al. 2017

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“…These pioneering studies showed how powerful could be the use of BA catalysis for asymmetric synthesis. BINOL-derived catalysts are designed in order to get an environment both sterically demanding and moderately acid, in order to achieve good enantioselectivity and to protonate the imine nitrogen [72]. While the first studies do not elucidate the specific mechanistic pathway (even though they suggest the protonation of the imide by the phosphoric acidic site), later on, the BA catalytic activity came up.…”

Section: Brønsted Acid Catalysismentioning

confidence: 99%

Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

Federsel¹

2014

ScienceOpen Research

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Organocatalysis, that is the use of small organic molecules to catalyse organic transformations, has been included among the most successful concepts in asymmetric catalysis and it has been used for the enantioselective construction of C-C, C-N, C-O, C-S, C-P, and C-halide bonds. Since the seminal works in early 2000, the scientific community has been paying an ever-growing attention to the use of organocatalysts for the synthesis, with high yields and remarkable stereoselectivities, of optically active fine chemicals of interest for the pharmaceutical industry. A brief overview is here presented about the two main classes of substrate activation by the catalyst: covalent organocatalysis and non-covalent organocatalysis, with a more stringent focus on some recent outcomes in the field of the latter and of hydrogen-bond-based catalysis. Finally, some successful examples of heterogenisation of organocatalysts are also discussed, in the view of a potential industrial exploitation.

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Chiral Brønsted Acids for Asymmetric Organocatalysis

Cited by 100 publications

References 94 publications

Catalytic Reductive ortho-C–H Silylation of Phenols with Traceless, Versatile Acetal Directing Groups and Synthetic Applications of Dioxasilines

Catalytic Reductive ortho-C–H Silylation of Phenols with Traceless, Versatile Acetal Directing Groups and Synthetic Applications of Dioxasilines

Acid- and Au(i)-mediated synthesis of hexathymidine-DNA-heterocycle chimeras, an efficient entry to DNA-encoded libraries inspired by drug structures

Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

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