Alder Reaction Of Danishefsky Research Articles

ChemInform Abstract: Copper‐Catalyzed Enantioselective Hetero‐Diels—Alder Reaction of Danishefsky′s Diene with Glyoxals.

The highly enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with glyoxals was developed by virtue of a readily accessible chiral copper catalyst. This efficient transformation provided a facile and scalable access to a wide range of biologically active dihydropyrones with a high level of enantioselectivities. Moreover, the substrate scope of this reaction could be extended to isatins with this catalytic system. More importantly, the mechanism involved in this reaction was proposed on the basis of the unambiguous structures of intermediates.

ChemInform Abstract: Asymmetric Hetero‐Diels—Alder Reaction of Danishefsky′s Diene with α‐Ketoesters and Isatins Catalyzed by a Chiral N,N′‐Dioxide/Magnesium(II) Complex.

AbstractThe title process tolerates a wide range of functional groups and provides dihydropyranones with excellent enantioselectivities.

ChemInform Abstract: Copper‐Catalyzed Enantioselective Hetero‐Diels—Alder Reaction of Danishefsky′s Diene with β,γ‐Unsaturated α‐Ketoesters.

AbstractThe first Cu‐catalyzed asymmetric Hetero‐Diels—Alder reaction of β,γ‐unsaturated α‐ketoesters with Danishefsky′s diene under mild reaction conditions is described.

Hetero-Diels–Alder Reaction of Danishefsky’s Diene with Keto Esters

Hetero-Diels–Alder Reaction of Danishefsky’s Diene with Keto Esters

ChemInform Abstract: Asymmetric Hetero‐Diels—Alder Reaction of Danishefsky′s Dienes with α‐Carbonyl Esters Catalyzed by an Indium(III)—PyBox Complex.

An efficient catalytic enantioselective hetero-Diels-Alder reaction of Danishefsky's dienes with α-carbonyl esters using a chiral In(III)-pybox complex has been demonstrated. This protocol offers several advantages, including mild reaction conditions, relatively low catalyst loading, and good to excellent enantioselectivities. Furthermore, the absolute configurations of the new alkynyl-containing products were determined by CD spectra in combination with TD-DFT calculations.

ChemInform Abstract: Oxo‐Diels—Alder Reaction of Danishefsky′s Diene with Aldehydes, Catalyzed by Chiral Tridentate Chromium(III)—Schiff Base Complexes.

AbstractThe reaction is highly effective in the presence of CSB.

ChemInform Abstract: BINOLate—Magnesium Catalysts for Enantioselective Hetero‐Diels—Alder Reaction of Danishefsky′s Diene with Aldehydes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

BINOLate–Magnesium Catalysts for Enantioselective Hetero‐Diels–Alder Reaction of Danishefsky's Diene with Aldehydes

AbstractAn efficient catalytic enantioselective hetero‐Diels–Alder reaction of Danishefsky's diene with aldehydes using the magnesium binaphthoxide system has been developed, affording a variety of 2‐substituted 2,3‐dihydro‐4H‐pyran‐4‐ones in high yields and with excellenteevalues. The aggregation behavior and nonlinear effect of the catalytic system, as well as the remarkable stereoelectronic effects of ligands on the catalysis, have also been investigated. On the basis of the structure of the isolated reaction intermediate, the stereochemistry of the products, and the information attained from a study of the nonlinear effect, a plausible asymmetric induction model has been proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

DIANANE‐CrIII‐salen Complexes as Highly Enantioselective Catalysts for Hetero‐Diels–Alder Reactions of Aldehydes with Dienes

AbstractA new type of chromium‐salen complex bearing DIANANE (endo,endo‐2,5‐diaminonorbornane) as chiral backbone has been synthesized and applied to the hetero‐Diels–Alder reaction of Danishefsky’s diene with various aldehydes. The reactions afford the corresponding 2‐substituted 2,3‐dihydro‐4H‐pyran‐4‐ones in high yields and enantioselectivities (up to 96 % ee). The effect of different counteranions of the complex on reactivity as well as enantioselectivity has been investigated. Besides Danishefsky’s diene, reaction of the less reactive 1‐methoxybutadiene with benzaldehyde and ethyl glyoxylate can be effected by the chromium catalysts as well.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Experimental and Theoretical Studies on the Hydrogen-Bond-Promoted Enantioselective Hetero-Diels−Alder Reaction of Danishefsky's Diene with Benzaldehyde

The enantioselective hetero-Diels-Alder (HDA) reaction of Danishefsky's diene with benzaldehyde has been achieved catalytically by a series of alpha,alpha,alpha',alpha'-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL) derivatives through hydrogen-bonding activation, affording 2-phenyl-2,3-dihydro-4H-pyran-4-one after trifluoroacetic acid workup in moderate yield and good enantioselectivity. The alpha,alpha'-aryl substituents in the TADDOL molecules are found to exert a significant impact on both the activity and the enantioselectivity of the catalysis. In combination with the experimental investigations, the mechanism of the present reaction has also been studied theoretically using the ONIOM (B3LYP/6-31G:PM3) method with trans-1,3-dimethoxy-1,3-butadiene as the model for Danishefsky's diene. In agreement with the experimental findings, the calculation results indicate that this TADDOL-catalyzed HDA reaction proceeds via a concerted mechanism through an asynchronous and zwitterionic transition structure (TS). The carbonyl group of benzaldehyde is activated by forming an intermolecular hydrogen bond with one of the hydroxy groups of TADDOL. Meanwhile, the intramolecular hydrogen bond between the two hydroxy groups in TADDOL is found to facilitate the intermolecular hydrogen bonding with benzaldehyde. The sense of asymmetric induction is well-rationalized by the analysis of the relative energies of TADDOL-complexed TSs, while the different stereocontrol capabilities exhibited by TADDOLs in the reaction can be qualitatively established on the basis of the structural features of their corresponding TSs.

Ionic Liquid Promoted Aza‐Diels—Alder Reaction of Danishefsky′s Diene with Imines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

3,3′‐Br2‐BINOL‐Zn Complex: A Highly Efficient Catalyst for the Enantioselective Hetero‐Diels—Alder Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Montmorillonite K10 Catalyzed Aza Diels—Alder Reaction of Danishefsky′s Diene with Aldimines, Generated in situ from Aliphatic Aldehydes and Amine, in Aqueous Media.

The montmorillonite K10-catalyzed aza Diels-Alder reaction of Danishefsky's diene with aldimines, generated in situ from aliphatic aldehydes and p-anisidine, proceeded smoothly in H 2 O or in aqueous CH 3 CN to afford 2-substituted 2,3-dihydro-4-pyridones in excellent yields.

ChemInform Abstract: Highly Efficient Enantioselective Synthesis of Optically Active Dihydropyrones by Chiral Titanium(IV) (5,5′,6,6′,7,7′,8,8′-Octahydro-1,1′-bi-2-naphthol) Complexes.

The asymmetric hetero-Diels–Alder reaction of Danishefsky’s diene and an aldehyde catalyzed by 20 mol% chiral H8-BINOL–Ti(IV) affords the corresponding 2-substitutent-2,3-dihydro-4H-pyran-4-one with ees of up to 99% under mild reaction conditions.

Highly efficient enantioselective synthesis of optically active dihydropyrones by chiral titanium(iv) (5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-bi-2-naphthol) complexes

The asymmetric hetero-Diels–Alder reaction of Danishefsky’s diene and an aldehyde catalyzed by 20 mol% chiral H8-BINOL–Ti(IV) affords the corresponding 2-substitutent-2,3-dihydro-4H-pyran-4-one with ees of up to 99% under mild reaction conditions.