An asymmetric normal-electron-demand aza-Diels-Alder cycloaddition of 2-aryl-3H-indol-3-ones and 2,4-dienals was explored via trienamine catalysis of a chiral secondary amine. Multifunctional tricyclic polyhydropyrido[1,2-a]indoles were efficiently constructed in good stereoselectivity (up to 92% ee, >19 : 1 dr).

Key words (±)-talatisamine - Diels–Alder reaction [2+2] photo-cycloaddition Lemieux–Johnson oxidation retro-aldol–aldol Wagner–Meerwein rearrangement aza-Prins

Diels-Alder cycloaddition between cyclopentadiene and p-benzoquinone has been studied in the confined space of a pure silica zeolite Beta and the impact on reaction rate due to the concentration effect within the pore and diffusion limitations are discussed. Introduction of Lewis or Brønsted acid sites on the walls of the zeolite strongly increases the reaction rate. However, contrary to what o...

regioselective diels-alder reactions of acyl-1,4-benzoquinones 1 with, severally, isoprene, trans-piperylene,1-acetoxy-1,3-butadiene and 1-methoxy-1,3-butadiene gave the corresponding adducts 2 in high yield. treatment of the adducts 2 with manganese dioxide gave regiospecifically the corresponding 1,4-naphthoquinones 3. in several cases, the adducts of the acetylquinones afforded intermediates...

3. Synthetic Applications 1746 3.1. Pericyclic Reactions 1747 3.1.1. Diels−Alder Cycloadditions 1747 3.1.2. Dipolar Cycloadditions 1749 3.1.3. Ene Reactions 1750 3.1.4. Claisen Rearrangements 1750 3.2. Radical Cyclizations 1750 3.3. Transition-Metal-Catalyzed Cyclizations 1753 3.4. Ring-Closing Metathesis 1754 3.5. Electrophilic Cyclizations 1755 3.6. Other Cyclizations 1756 4. Biochemical and ...

in the present work, the regioselectivity for a series of diels–alder reactions (4 reactions) has beenstudied using hardness, electrophilicity and polarizability of products.furthermore,thermodynamicand kinetic calculations have been done. in all results predicted pararegioisomer is more favorableregioisomerinthese investigated reactions.all calculations have been done at the dft-b3lyp/6-31g(d)...

Detailed analysis of calculated data from an experimental/computational study of intramolecular furan Diels-Alder reactions has led to the unusual discovery that the mean contraction of the newly forming C-C σ-bonds from the transition state to the product shows a linear correlation with both reaction Gibbs free energies and reverse energy barriers. There is evidence for a similar correlation i...

A fascinating aspect of the Diels–Alder reaction is its endo selectivity. This endo preference is much less pronounced in intermolecular cases compared with the intramolecular and transannular Diels–Alder (IMDA and TADA) reactions. Nevertheless, high endo selectivity is observed in the Diels– Alder additions of (E)-1-O-substituted dienes catalyzed by Lewis acids that lead to cis-1,6-disubstitut...

The pyridazino[4,5-b]indole (3), which is conveniently available from 3-methylthioindole and the tetrazine (2), undergoes thermally induced inverseelectron-demand Diels-Alder reactions with enamines to afford the cycloalkeneannelated carbazoles (7,8) or the 2-substituted carbazole (9), respectively. We have previously shown that 1,2-diazines annelated to a second π-electron-deficient aromatic r...

One of the most efficient methods (high yield, controlled stereochemistry, diverse functionality) to construct rings from smaller fragments is via cycloaddition reactions. The reverse reaction, namely splitting of a ring into smaller fragments is termed a cycloreversion reaction is also an important synthetic tool. (For example, in the present experiment it is the cracking of cyclopentadiene di...