SYNTHESIS OF AROMATIC HETEROCYCLES CONSTRUCTION OF THE RING SKELETON

Jan 06, 2025

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Explore innovative methods like carbonyl condensation reactions, cycloadditions, nitrene insertions for crafting aromatic heterocycles. Learn techniques for synthesizing 5-membered rings (Pyrrole, Furan, Thiophene) and 6-membered rings with enols and enamines. Discover the power of 1,3-dipolar cycloadditions and ortho-quinodimethanes in forming diverse ring structures. Unravel the intricacies of nitrene insertion and generation for efficient heterocyclic synthesis.

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SYNTHESIS OF AROMATIC HETEROCYCLES CONSTRUCTION OF THE RING SKELETON

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SYNTHESIS OF AROMATIC HETEROCYCLES CONSTRUCTION OF THE RING SKELETON • Carbonyl condensation type reactions • Cycloadditions • with 1,3-dipoles • with ortho-quinodimethanes (DA type react.) • Nitrene insertion Carbonyl condensations
Strategy a) - 5-membered rings Pyrrole (Paal-Knorr Synthesis s 255) Furan Thiophene
Strategy a) - 6-membered rings
Strategy b 5-membered rings Enol (or phenol) 6-membered rings Enamin (or anilin)
1,3-Dipolar Cycloaddition 1,3-dipol Only 5-membered rings Alkene / alkyne Ex. ozonolysis
Cycloaddition with ortho-Quinodimethanes Electrocyclic ring opening
Nitrene Insertion Generation of nitrenes
React. of nitrenes
Nitrene insertion - Heterocyclic synthesis