Aqueous-phase, thermal Pauson–Khand reactions in the presence of surfactants
✍ Scribed by Marie E. Krafft; James A. Wright; Llorente V.R. Boñaga
- Book ID
- 104253330
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- French
- Weight
- 319 KB
- Volume
- 44
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Efficient stoichiometric Pauson-Khand reactions were realized in water as the only solvent, and in the presence of surfactants as additives. Use of the cationic surfactant CTAB provided good yields of cyclopentenones from the thermal reactions of pre-formed dicobalthexacarbonyl complexes of enynes and alkynes. The water-CTAB medium was found to be less effective with Co 4 (CO) 12 as the promoter of the reaction. Incidentally, these results have provided a strictly water-based PKR protocol under very mild and convenient conditions.
📜 SIMILAR VOLUMES
Dicobaltoctacarbonyl, [Co 2 (CO) 8 ], has always been the metal complex of choice in the widely used Pauson ± Khand reaction for the formation of bicyclo[3.3.0]octenones by the cyclocarbonylation of an alkene and an alkyne (Scheme 1). [1] Alternative sources of zero valent cobalt, namely [(indenyl)C
Khand cycloaddition. Several methods have been reported to increase the rate of the intramolecular Pauson-Khand cycloaddirion.2\*3 These include performing the reaction in the presence of 4-methylmorpholine N-oxide4 or trimethylamine N-oxide' in CH.&l,, or carrying out the reaction in the dry state