Catalyzed Addition of Aldehydes to Activated Double Bonds—A New Synthetic Approach

Abstract

In the presence of cyanide ions as catalyst, aromatic and heterocyclic aldehydes can be smoothly added to ct,P-unsaturated ketones, esters, and nitriles in aprotic solvents to form y-diketones, 4-0x0 carboxylic esters, and 4-ox0 nitriles. Thiazolium salts in the presence of bases are also suitable catalysts; they permit not only addition of aromatic and heterocyclic aldehydes but also the addition of aliphatic aldehydes.

Synthesis and characterization of novel substituted pyrrole, thiophene and furans

“…20,21 The most versatile general 1,4-dicarbonyl synthesis is known as the Stetter reaction, 42,43 which is the catalyzed conjugate addition of an aldehyde to a Michael acceptor such as an enone. Thiazolium salt, 44 cyanide ion, 45,46 and tributylphosphine 47 are used as the catalyst in the presence of a base. The effectiveness of the procedure depends significantly upon the choice of the catalysts.…”

Studies toward the synthesis of angularly-oxygenated angucyclines antibiotics

“…The first annulating strategy we considered was an intramolecular thiazolium ion-catalyzed aldehyde-ketone benzoin-type condensation (Scheme 3). 40,41 No cyclization was observed under the conditions applied, the only product isolated after heating 8 at 80 °C in absolute ethanol and in the presence of thiazolium chloride 12 and triethylamine was the thermally-induced Cope rearrangement product 16 (90%) (Scheme 3). The reaction performed at lower temperature only led to the recovery of starting material.…”

1,3-Bis(2,6-diisopropylphenyl)-2-trichloromethylimidazolidine

“…Although carbenes are typically used as ligands for transition metals [11][12][13][14][15], or as nucleophilic organic catalysts [16][17][18][19][20][21][22][23][24][25], these carbene derivatives that contain an (H)CCl3 bound at the carbene C2 position have been found through reductive thermolysis, to give free carbene for reaction with metals [26].…”