Studies toward the enantiospecific total synthesis of rhodexin A via a very hindered inverse electron demand Diels-Alder reaction are described. The C8-diastereomer of the fully elaborated tetracyclic core of rhodexin A, 23, was prepared in good yield and excellent selectivity using as the key step the stepwise Diels-Alder reaction of the very hindered dienone 3 and the silyl enol ether 4 catal...

A metal-free and formal [2 + 2 + 2] cycloaddition of triynes has emerged recently as a novel methodology for the synthesis of fused tricyclic compounds via an intramolecular cascade propargylic ene reaction, Diels-Alder cycloaddition and tautomerization. DFT calculations on three model systems reveal that the ene reaction with low distortion energy makes the metal-free strategy feasible and, as...

There is currently a tremendous interest in developing bioorthogonal "click chemistry" methods for the modification of biopolymers. Very recently, inverse-electron-demand Diels-Alder reactions have received attention, but to date they have not been applied to nucleic acids. Here we describe the first example of DNA modification by inverse-electron-demand Diels-Alder reaction. We synthesized fou...

During the last two decades, organic reactions in aqueous media have been attracting increasing attention. Furthermore, It has been established that some DielsAlder reaction dramatically accelerated in aqueous media. These have been alternatively ascribed to hydrophobic association of the reacting partners, micellar catalysis, solvophobicity, high internal solvent pressure, cohesive energy dens...

Enyne alcohols can react as precursors of either dienes or dienophiles with different substrates after hydroxylation and isomerization by gold catalysis. As such, oxa-bridged tricyclo[5.2.2.02,6]-undec-8-ene-3,5-dione derivatives have been obtained by the Diels–Alder reaction and tetrahydro-1H-furo[3,4-c]pyran derivatives could be accessed by the hetero-Diels–Alder cycloaddition.

The first total synthesis of monosporascone is presented. The five-step synthesis developed includes a silver acetylide-acid chloride coupling, domino Diels-Alder-retro-Diels-Alder reaction, and an intramolecular Friedel-Crafts acylation, and provides the natural product in 57% yield overall. Selective reduction of monosporascone also afforded the related metabolite dihydromonosporascone.

Chemical redox reactions have been exploited to transform unreactive vinylferrocene into a powerful dienophile for the Diels-Alder reaction and reactive substrate for thiol addition reactions upon conversion to its ferrocenium state. We have further investigated the ability of these reactions to facilitate redox-auxiliary-like reactivity by further hydrogenolyisis of the Diels-Alder adduct to t...

[reaction: see text] Two different routes to the tricyclic core of Garcinia-derived natural products are described. The first approach is based on a tandem Claisen/Diels-Alder rearrangement and delivers the desired lactone 14. The second approach, employing a Wessely oxidation/Diels-Alder protocol, leads to the same caged heterocycle, albeit with modified constitution.

Here we found that the enantioselectivity of G-quadruplex DNA-based Diels-Alder reaction can be switched by just changing Na(+) to K(+), which is ascribed to the structural transformation of the G-quadruplex from antiparallel to hybrid-type. By tuning the ratio of Na(+)/K(+), the enantioselectivity of the Diels-Alder reaction could be switchable and shows much more sensitive to K(+) than to Na(+).

A concise synthesis of forbesione (1) and desoxymorellin (3) is presented. Central to the strategy is a biomimetic Claisen/Diels-Alder/Claisen reaction cascade that proceeds in a regioselective manner and produces the desired scaffold exclusively. The observed regioselectivity and product distribution of the Claisen/Diels-Alder/Claisen reaction are attributed to the electronic effects of the xa...