Stereoselective Diels-Alder Reaction Research Articles

ChemInform Abstract: Asymmetric Diels-Alder Reactions: EPC-Synthesis of a Stable Sarkomycin Precursor.

The key step in the synthesis of the cyclosarkomycin (IX) is the stereoselective Diels-Alder reaction of the chiral bromoacrylate (Ia) with cyclopentadiene (II) to form mainly the cycloadduct (IIIa).

Stereoselective diels-alder reactions of a new chiral carbamoylnitroso compound

A new chiral carbamoylnitroso dienophile 1 has been prepared from a substituted pyrrolidine possessing C 2 symmetry. Compound 1 reacts with dienes to yield (4 + 2) cycloadducts with very high diastereoisomeric excesses.

Stereoselective diels-alder reactions of a new chiral carbamoylnitroso compound.

Stereoselective diels-alder reactions of a new chiral carbamoylnitroso compound.

A stereoselective biocatalytic diels-alder reaction

Baker's yeast catalyzes the stereoselective Diels-Alder reaction of cyclopentadiene 1 with dienophiles 2 , 4 and 6 . A predominant formation of exo isomer is observed in some cases.

Formation and photochemical rearrangement of carbon-oxygen-linked anthracenes

Alkyl esters of 9-anthrilic acid isomerize both thermally and photochemically by stereoselective Diels-Alder reaction, while treatment with base induces the shift of 9-anthryl from carbon to oxygen. Photoexcitation of carbon-oxygen-linked bichromophoric anthracenes results in a migratory 9-anthryloxy - 9-anthronyl rearrangement.

A completely stereoselective intramolecular diels-alder reaction in the substituted cyclohexanol series

Subtituted dienyl cyclohexanols, obtained through opening of cyclohexene oxide by dienyl aluminum reagents, are easily esterified with acryloyl, crotonyl or methacryoyl chloride or with maleic anhydride. These esters undergo a completely stereoselective Lewis acid catalyzed Diesels-Alder reaction. The obtained product were characterized by X-ray crystallography.

Some aspects of the reactivity of RCu/BF 3 reagents towards the ether linkage

Organocopper reagents associated with a strong Lewis acid such as BF 3 react with the C— O single bond of orthoesters, acetals and epoxides. The diastereoselective cleavage of chiral acetals opens a new way of obtaining chiral secondary alcohols or chiral (3-substituted aldehydes. A partial synthesis of the pherom one of the California red scale uses this approach. The opening of hindered epoxides is also very efficient with R 2 CuLi/BF 3 reagents. Thus reaction with epoxy-silane gives rise to conjugated dienes as illustrated with the synthesis of the pheromones of Lobesia botrana and of Bombyx mori. Cyclohexene oxide reacts in the same way with R 4 AlLi/BF 3 and the dienyl substituted cyclohexanols, thus obtained, can be used in highly stereoselective intram olecular Diels-Alder reactions.

ChemInform Abstract: Structure and Electronic Nature of the Benzaldehyde/Boron Trifluoride Adduct

The structure of the benzaldehyde/boron trifluoride adduct (6) has been determined by X-ray crystallography. Accordingly, the Lewis acid BF3 is complexed anti to the phenyl group in benzaldehyde. The B-OC-C fragment lies essentially in a common plane. Anti complexation also pertains in solution, as shown by a heteronuclear Overhauser experiment. MNDO calculations of the acetaldehyde/BF, adduct show that anti complexation does indeed lead to the lowest energy species. However, the syn adduct lies only 1.8 kcal/mol higher in energy. The linear form does not represent a minimum on the energy surface but rather the lowest energy transition state for intramolecular anti * syn isomerization. The calculations of CH,CHO/BF,, of 6, and of the free aldehydes clearly point to LUMO lowering and to an increased positive charge at the carbonyl carbon atom upon complexation. The results are discussed in light of Lewis acid mediated aldehyde additions involving allyl and enolsilanes, stannanes, and cyanotrimethylsilane as well as such processes as Diels-Alder, ene, and Grignard reactions. A wide variety of C-C bond-forming reactions of carbonyl compounds are mediated by Lewis acids such as BF3, AICI,, EtAlCI,, TiCI4, SnC1,. and ZnX,. They include carbonyl additions of allylsilanes, enosilanes, cyanotrimethylsilane, and other silyated' and stannylated* carbon nucleophiles, as well as ene reaction^,^ Diels-Alder addition^,^ and hetero-Diels-Alder cycloconden~at ions.~ It is generally accepted that the Lewis acid activates the carbonyl component by forming an adduct prior to C-C bond formation. Whereas X-ray crystallographic data of a TiCI4 adduct of a chiral acrylic acid ester has recently been reported and discussed with regard to stereoselective Diels-Alder reactions,6 precise structural information concerning complexes of aldehydes with the above-mentioned Lewis acid remains to be presented. N M R , UV, and I R data of common aldehyde/Lewis acid complexes are available, but they do not answer the question of anti vs. syn complexation (1 vs. 2; MX, = Lewis acid).' A great deal of experimental and theoretical work concerning the interaction of formaldehyde with Li+ and other Lewis acids has accumulated ' Philipps-Universitat. 'Universitat Essen. R H KMX

Novel dienes from α-ylidene and α-alkoxylidene lactones. Useful intermediates for the synthesis of benzofurans

Novel dienes, formed by reaction of α-ylidene and α-alkoxylidene lactones with the lithium salt of acetonitrile, are readily converted into benzofuran precursors by a highly regioselective (and in the case of the former derivatives) a highly stereoselective Diels–Alder reaction.

ChemInform Abstract: REGIO‐ AND STEREOSELECTIVITY IN DIELS‐ALDER REACTIONS. THEORETICAL CONSIDERATIONS

Chemischer InformationsdienstVolume 16, Issue 5 Reviews ChemInform Abstract: REGIO- AND STEREOSELECTIVITY IN DIELS-ALDER REACTIONS. THEORETICAL CONSIDERATIONS R. GLEITER, R. GLEITERSearch for more papers by this authorM. C. BOEHM, M. C. BOEHMSearch for more papers by this author R. GLEITER, R. GLEITERSearch for more papers by this authorM. C. BOEHM, M. C. BOEHMSearch for more papers by this author First published: February 5, 1985 https://doi.org/10.1002/chin.198505357AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume16, Issue5February 5, 1985 RelatedInformation

Acceleration of the diels-alder reaction by clays suspended in organic solvents

Rapid and stereoselective Diels-Alder reactions can be run in ethanol or methylene chloride in the presence of Fe III- doped K10 montmorillonite.

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Two successful syntheses of cytochalasins accomplished at Columbia University are described in a context of general problems associated with the synthesis of this class of compounds. The key features of the syntheses involve a regio- and stereoselective Diels-Alder reaction of an enol lactam, e. g., 57, and a triene, e. g., 49, followed by stereocontrolled formation of 6, 7-epoxide (to cytochalasin F, 3), which is then transformed to Δ6 (12) -allylic alcohol (to cytochalasin B, 2). The first synthesis solved these fundamental structural problems and the second streamlined the overall strategy by using a macrocyclic internal Diels-Alder reaction and some new phosphorus and aluminium reagents.

Regio- and stereoselectivity in Diels-Alder reactions. Theoretical considerations

Abstract

Stereoselective diels-alder reactions between 9-alkyl-1,4-dihydronaphthalen-1,4-imines and 2-alkylisoindoles

The Diels-Alder reaction between 9-alkyl-1,4-dihydronaphthalen-1,4-imines ( 1 ) and 2-alkylisoindoles ( 2 ) occurs in refluxing xylene to give exclusively the exo-endo cyclo-adducts 3 ( D ).

ChemInform Abstract: CHEMISTRY OF ELECTRON‐RICH CONJUGATED POLYENES. V. REGIO‐ AND STEREO‐SELECTIVITY IN DIELS‐ALDER REACTIONS OF 1‐ALKOXY‐1,3‐BUTADIENES AND β‐CYANOSTYRENES

AbstractDiels‐ Alder‐Reaktion des Diens (I) mit den Dinitrilen (II) führt zu trennbaren Gemischen der Isomeren (III) und (IV) (Untersuchung der Konformationen); aus entsprechenden (I)‐Analogen und Dinitrilen (II) werden ähnlich die Gemische (V) + (VI), (VII) + (VIII) sowie (IX) + (X) gewonnen.

Stereoselective syntheses of lycopodium alkaloids, (±)-fawcettimine and (±)-8-deoxyserratinine

Lycopodium alkaloids, (±)-fawcettimine (1) and (±)-8-deoxyserratinine (3) were stereoselectively synthesized through the stereoselective Diels-Alder reaction and the regioselective aldol condensation reaction of the dialdehyde (8).

A new estimation of secondary interactions controlling the stereoselectivity of diels-alder reactions

A new estimation of secondary interactions controlling the stereoselectivity of diels-alder reactions

The Correlation of Solvent Effects on the Stereoselectivities of Diels-Alder Reactions by Means of Linear Free Energy Relationships. A New Empirical Measure of Solvent Polarity

<b>The Correlation of Solvent Effects on the Stereoselectivities of Diels-Alder Reactions by Means of Linear Free Energy Relationships. A New Empirical Measure of Solvent Polarity</b>

Solvent effects on the stereoselectivity of diels-alder reactions

Solvent effects on the stereoselectivity of diels-alder reactions