The Dienyl Pauson—Khand Reaction.

✍ Scribed by Paul A. Wender; Nicole M. Deschamps; Gabriel G. Gamber

• Publisher: John Wiley and Sons
• Year: 2003
• Weight: 171 KB
• Volume: 34
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.200333084

✦ Synopsis

Cyclopentane derivatives

Cyclopentane derivatives Q 0030

The Dienyl Pauson-Khand Reaction. -The reaction of dienyne (I) with CO produces a mixture of the cycloadducts (III), (IV) and (V). The formation of (V) represents a new [4 + 2 + 1] cycloaddition reaction for the construction of seven-membered rings, while the formation of alkenylcyclopentenone (IV) represents a new class of Pauson-Khand reaction. After optimization of the reaction (temperature, solvent, catalyst concentration, CO pressure), conditions for selective Pauson-Khand reaction are found. The new [2 + 2 + 1] reaction produces alkenylcyclopenones in good to excellent yields under mild conditions and low catalyst loadings (1-2.5 mol%). Substitution of the diene is well tolerated and allows the facile diastereoselective construction of quaternary centers. -(WENDER*,