Soluble Polymer‐Supported Organocatalysts: Asymmetric Reduction of Imines with Trichlorosilane Catalyzed by an Amino Acid Derived Formamide Anchored to a Soluble Polymer

Malkov, Andrei V.; Figlus, Marek; Prestly, Mark R.; Rabani, Gouher; Cooke, Graeme; Kočovský, Pavel

doi:10.1002/chem.200901573

Cited by 30 publications

(12 citation statements)

References 46 publications

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“…A further recyclable catalytic system was produced by anchoring the chiral active species to a new soluble polymeric platform (a block polymethacrylate) that, unlike the classic soluble supports (e.g., PEG), is soluble in apolar solvents and can be precipitated by increasing the solvent polarity 15. Asymmetric reductions of imines with Cl 3 SiH promoted by the soluble polymeric platform 7 (1–7 mol‐% catalyst loading) proceed at room temperature, affording chiral amines in high yields and with good enantioselectivities (≤91 % ee ).…”

Section: Discussionmentioning

confidence: 99%

Trichlorosilane‐Mediated Stereoselective Reduction of C=N Bonds

2010

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The reduction of C=N bonds represents a powerful and widely used transformation allowing new nitrogen‐containing stereocenters to be generated. Chiral amino groups are ubiquitous in a variety of bioactive molecules such as alkaloids, natural products, drugs, and medical agents, so the development of a catalytic stereoselective process for the preparation of enantiomerically enriched amines through ketoimine reduction is attracting increasing interest, especially in view of future industrial applications. Great efforts to develop efficient organocatalytic methods to perform enantioselective imine reductions and reductive amination processes have recently been made. In the last few years, trichlorosilane‐mediated reductions have received constantly increasing attention because the potential to generate chiral catalysts for imine reduction simply by coordination of HSiCl3 with a chiral Lewis base has allowed the development of several efficient organocatalytic systems. Here we offer a complete overview of different chiral promoters of stereoselective reductions with trichlorosilane, classified as N‐formyl derivatives, which may be considered historically the first class of compounds developed as chiral activators of trichlorosilane, picolinamide derivatives, and miscellaneous compounds presented in that order.

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Section: Discussionmentioning

confidence: 99%

Trichlorosilane‐Mediated Stereoselective Reduction of C=N Bonds

2010

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“…The same research group designed a soluble catalyst 102 with the main aim of avoiding the problems associated with the heterogeneous systems, and related to the common supported catalysts. [92] The main advantage of this system is the inverted solubility pattern that this catalyst exhibits, since it is soluble in non-polar solvents and insoluble in polar media (Figure…”

Section: Supported Lewis Base Organocatalystsmentioning

confidence: 99%

Organocatalytic Transfer Hydrogenation and Hydrosilylation Reactions

Herrera

2016

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The reduction of different carbon-carbon or carbon-heteroatom double bonds is a powerful tool that generates in many cases new chiral centers. In the last decade, the organocatalytic version of these transformations has attracted more attention, and remarkable progresses have been made in this way. Organocatalysts such as chiral Brønsted acids, thioureas, chiral secondary amines or Lewis bases have been successfully used for this purpose. In this context, this chapter will cover pioneering and seminal examples using Hantzsch dihydropyridines 1 and trichlorosilane 2 as reducing agents. More recent examples will be also cited in order to cover as much as possible the complete research in this field.

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“…Recycling studies (fi ve cycles) were carried out using 200f in 20 mol% with unchanged activity and enantioselectivity [164] . Soluble polymer -supported catalyst 200f had as its main advantage, with respect to the latter catalytic systems, the increased enantioselectivity compared to the heterogeneous catalysts and the almost quantitative recovery after precipitation with methanol.…”

Section: Asymmetric Reductionmentioning

confidence: 99%