Acetylenic ureas readily undergo oxidative cyclization-alkoxycarbonylation reactions in the presence of PdI2 (or Pd:C)-KI as catalyst in methanol under mild conditions (65°C and 24 bar of a 3:1 mixture of CO and air). Cyclization occurs by trans-attack of oxygen or cis-attack of nitrogen functions on the triple bond, followed by stereospecific carbonylation, resulting in E or Z-stereochemistry, respectively. In the case of diacetylenic ureas condensed ring formation occurs. The triple bond can also react stereospecifically with carbon monoxide and methanol to form a maleic group by cis-attack leading to Z-stereochemistry.

Nitrogen heterocycles by palladium-catalysed oxidative cyclization-alkoxycarbonylation of acetilenic ureas

GABRIELE, Bartolo;
1998

Abstract

Acetylenic ureas readily undergo oxidative cyclization-alkoxycarbonylation reactions in the presence of PdI2 (or Pd:C)-KI as catalyst in methanol under mild conditions (65°C and 24 bar of a 3:1 mixture of CO and air). Cyclization occurs by trans-attack of oxygen or cis-attack of nitrogen functions on the triple bond, followed by stereospecific carbonylation, resulting in E or Z-stereochemistry, respectively. In the case of diacetylenic ureas condensed ring formation occurs. The triple bond can also react stereospecifically with carbon monoxide and methanol to form a maleic group by cis-attack leading to Z-stereochemistry.
Carbonylation; Heterocycles; Palladium
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/146808
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