Bibliographic Details
| Title: |
Palladium-Catalysed Alkynylations of 2-Pyrone (Pyran-2-one) Halides. |
| Authors: |
Fairlamb, Ian J.S., Feng Ju Lu, Ian J.S., Schmidt, Jan Peter |
| Source: |
Synthesis; Nov2003, Vol. 2003 Issue 16, p2564-2570, 7p, 1 Diagram, 3 Charts |
| Subject Terms: |
HALIDES, PALLADIUM catalysts, CATALYSIS, CYCLIC compounds, ORGANIC synthesis, PALLADIUM |
| Abstract: |
The 2-pyrone sub-unit is found in a large number of natural products possessing broad-spectrum biological activity. As such, efficient synthetic methods are required to enable facile access to substituted 2-pyrone derivatives. Important conditions for the Sonogashira alkynylation of 4-bromo-6-methyl-2-pyrone (3a) have been developed, and compared against Negishi's methodology. The best conditions for Sonogashira alkynylation was found to be the use of Pd/C with added Ph[sub 3]P as the catalyst, in the presence of catalytic CuI, in a mixture of MeCN and Et[sub 3]N at reflux. Using Negishi's standard conditions, terminal alkynylzinc reagents, generated in situ from terminal alkynes with LDA or n-BuLi and subsequent reaction with anhydrous ZnBr[sub 2], were reacted with 3a at room temperature using Pd(PPh[sub 3])[sub 4] as the catalyst in THF. [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |
