A new functional polymer where proline is bonded to polystyrene through a 1,2,3-triazole linker depicts characteristics targeted for an artificial aldolase. In spite of the hydrophobicity backbone, resin swells in water with building aqueous microenvironment. This property, arising from formation hydrogen-bond network connecting and fragments, translated into very high catalytic activity enantioselectivity toward direct aldol reactions water.

The fast and highly stereoselective Mannich reaction of aldehydes ketones with the N-(p-methoxyphenyl) ethyl glyoxylate imine catalyzed by polystyrene resins functionalized (2S,4R)-hydroxyproline is reported. effect nature linker connecting proline polymeric backbone has been studied, a 1,2,3-triazole constructed from azidomethyl O-propargyl hydroxyproline turns out to be optimal for catalytic activity enantioselectivity. With aldehyde donors, reactions leading complete conversion in 1-3 h...

The first catalytic enantioselective α-aminoxylation of aldehydes and ketones using an insoluble, polymer-supported organocatalyst (1) derived from trans-4-hydroxyproline is reported (ee: 96−99%). Reaction rates in the aminoxylation cyclic with 1 are higher than those l-proline. insoluble nature simplifies workup conditions allows catalyst recycling without apparent decrease enantioselectivity or yield.

α,α-Diphenylprolinol methyl- and trimethylsilyl ethers anchored onto a polystyrene resin have been prepared by copper-catalyzed azide-alkyne cycloadditions (CuAAC). The catalytic activity enantioselectivity displayed the O-trimethylsilyl derivative are comparable to those exhibited best known homogeneous catalysts for addition of aldehydes nitroolefins malonates or nitromethane α,β-unsaturated aldehydes. combination unit, triazole linker, polymeric matrix provides unprecedented substrate...

Abstract Polystyrene (PS)‐supported diphenylprolinol silyl ethers have been developed as highly active catalysts for the enantioselective α‐amination of aldehydes. Understanding mechanism catalyst deactivation has led to development reaction conditions notably extending life in repeated recycling (10 cycles; accumulated TON 480) and allowed implementation a continuous flow process (6 min residence time, 8 h operation).

A set of six solid-supported diarylprolinol catalysts (varying on the anchoring strategy and type polymeric support) has been prepared applied to enantioselective cyclopropanation reaction. The selected candidate allows implementation a long flow experiment (48 h) generates library 12 cyclopropanes by sequential experiments. mildness utility method have enabled telescoped process in which outstream is directly used Wittig

Faster than believed: Transmetalation from aryl boronic acids and triaryl boroxines to diethylzinc takes place within minutes following a two-step, low-energy pathway (see picture), according density functional calculations reaction microcalorimetry measurements. The experimental conditions for practical, atom-economical, highly enantioselective catalytic arylation of variety aldehydes have been developed these data.

Abstract A family of enantiopure diphenylphosphinooxazolines (PHOX) containing in their structures a sterically tunable alkoxymethyl group (‐CH 2 OR) has been optimized for the palladium‐catalyzed asymmetric allylic amination. The optimal catalyst (R=CH 3 ), depicting very high catalytic activity and broad scope applicability, further modified to include an ω‐alkynyloxy substituent variable length polymer supporting via click chemistry , anchored onto slightly cross‐linked azidomethyl...

A polystyrene-supported, pyrrolidine-based catalyst depicting very high activity and excellent stereoselectivity in the anti-Mannich reaction of aldehydes ketones has been developed. The robust, immobilized successfully used implementation a continuous flow process with short residence times (down to 6 min) for production highly enantioenriched anti-type Mannich adducts at preparative scale.

A novel polymer-supported fluorinated organocatalyst has been prepared and benchmarked in the enantioselective Michael addition of aldehydes to nitroalkenes. The system proven be highly efficient displays excellent selectivities (er dr) with a wide variety substrates. Detailed deactivation studies have given valuable insights, thus allowing lifespan this immobilized aminocatalyst significantly extended. These data facilitated implementation enantioselective, continuous flow processes either...

The application of polystyrene-immobilized proline-based catalysts in packed-bed reactors for the continuous-flow, direct, enantioselective α-aminoxylation aldehydes is described. system allows easy preparation a series β-aminoxy alcohols (after reductive workup) with excellent optical purity and an effective catalyst loading ca. 2.5% (four-fold reduction compared to batch process) working at residence times ca . 5 min.

A song of ice and fire! The usually innocent paraldehyde can be used as an acetaldehyde precursor in organocatalytic asymmetric Michael addition (see scheme) thanks to the proper combination two immobilized catalysts. site isolation induced by polymeric supports has proven crucial preclude deactivation otherwise incompatible

Lighten the load! A family of enantiopure 4-oxy-substituted 3-aminopyrrolidines arising from enantioselective ring-opening meso-3-pyrroline oxide have been developed as catalysts for asymmetric, anti-selective Mannich reaction (see scheme; PMP=p-methoxyphenyl; PG=protecting group). Very high catalytic activity (down to 0.01 mol % loading) and stereoselectivity recorded. Detailed facts importance specialist readers are published "Supporting Information". Such documents peer-reviewed, but not...

Abstract A new family of polystyrene‐supported cis ‐4‐hydroxydiphenylprolinol silyl ethers has been prepared, and the resulting polymers have evaluated as organocatalysts to promote tandem reaction between N ‐protected hydroxylamines α,β‐unsaturated aldehydes in batch flow. The PS‐supported catalysts compare favorably with well‐established immobilized Jørgensen‐Hayashi catalysts, affording 5‐hydroxyisoxazolidines single diastereoisomers high enantioselectivities good yields (up 83% yield, up...

A PS-immobilized triazolylproline prepared by co-polymerization with full regiocontrol swells in water and catalyzes the enantioselective cross-aldol reaction self-aldol of aldehydes under essentially neat conditions excellent stereocontrol.

Polystyrene-supported (PS) diarylprolinol catalysts 1 a (Ar = phenyl) and b 3,5-bis(trifluoromethyl)phenyl) have been developed. Operating under site-isolation conditions, PS-1 a/1 worked compatibly with PS-bound sulfonic acid catalyst 2 to promote deoligomerization of paraldehyde subsequent cross-aldol reactions the resulting acetaldehyde in one pot, affording aldol products high yields excellent enantioselectivities. The effect water on performance catalytic system has studied its optimal...

Proline-functionalized VA-PNBs behave as active, recoverable and reusable organocatalysts for the asymmetric direct aldol reaction in aqueous media.

TMSCF3 adds to chiral 2-acyl-1,3-perhydrobenzoxazines with total diastereoselectivity leading quaternary trifluoromethyl alcohols. Further transformation of the addition products yields enantiomerically enriched trifluoromethylated 1,2-diols and 1,2-amino

Diarylprolinol silyl ethers immobilized onto polystyrene have been employed as catalysts in the enantioselective domino Michael-Knoevenagel reaction of dimethyl 3-oxoglutarate and 3-substituted acrolein derivatives, including aliphatic ones. The best catalyst allows preparation highly functionalized cyclohexane derivatives a straightforward efficient manner, both under batch continuous flow conditions.

Schneller als angenommen: Dichtefunktionalrechnungen und mikrokalorimetrischen Messungen zufolge ist die Transmetallierung von Arylboronsäuren Triarylboroxinen mit Diethylzink binnen Minuten beendet verläuft über einen zweistufigen Pfad niedriger Energie (siehe Bild). Die experimentellen Bedingungen für eine atomökonomische hoch enantioselektive katalytische Arylierung Aldehyden beruhen auf diesen Daten. Supporting information for this article is available on the WWW under...

[reaction: see text] Chiral precursors to the intramolecular Diels-Alder reaction using furan as a diene (IMDAF) have been prepared by diastereoselective addition of furyllithium imines attached perhydro-1,3-benzoxazines derived from (-)-8-aminomenthol. The acylation furylamines with alpha,beta-unsaturated acyl chlorides and subsequent IMDAF under thermal conditions provided corresponding cycloadducts single diastereoisomers. hydrolytic elimination chiral template yielded enantiopure...

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionToward an Artificial AldolaseDaniel Font, Sonia Sayalero, Amaia Bastero, Ciril Jimeno, and Miquel A. Pericàs*Cite this: Org. Lett. 2010, 12, 11, 2678Publication Date (Web):April 9, 2010Publication History Received31 March 2010Published online9 April inissue 4 June 2010https://pubs.acs.org/doi/10.1021/ol100738hhttps://doi.org/10.1021/ol100738hcorrectionACS PublicationsCopyright © 2010 American...

Borane complexes of phosphorus compounds, a very common oxidation-free relay for catalytic ligands (phosphines, phosphites, and phosphinites), can be easily deprotected by treatment with polymer-supported piperazine or N-methylpiperazine. Deprotection conditions have been optimized the different types resulting solutions used without any intermediate work-up purification process.