| Autor: |
Lenker HK; Department of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, USA., Richard ME, Reese KP, Carter AF, Zawisky JD, Winter EF, Bergeron TW, Guydon KS, Stockland RA Jr |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of organic chemistry [J Org Chem] 2012 Feb 03; Vol. 77 (3), pp. 1378-85. Date of Electronic Publication: 2012 Jan 13. |
| DOI: |
10.1021/jo202183u |
| Abstrakt: |
The addition of P(O)-H bonds to internal alkenes has been accomplished under solvent-free conditions without the addition of a catalyst or radical initiator. Using a prototypical secondary phosphine oxide, a range of substrates including cinnamates, crotonates, coumarins, sulfones, and chalcones were successfully functionalized. Highly activated acceptors such as isopropylidenemalononitrile and ethyl 2-cyano-3-methyl-2-butenoate underwent the phospha-Michael reaction upon simple trituration of the reagents at room temperature, whereas less activated substrates such as ethyl cinnamate and methyl crotonate required heating (>150 °C) in a microwave reactor to achieve significant consumption of the starting alkenes. For the latter alkenes, a competing reaction involving disproportionation of the ditolylphosphine oxide into ditolylphosphinic acid and ditolylphosphine was observed at the high temperatures needed to promote the addition reaction. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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