Abstract4,4‐Dimethoxy‐2,5‐cyclohexadienones 9–14 were prepared from the corresponding hydroquinone monomethyl ethers by oxidation with thallium trinitrate in methanol. Irradiation of solutions of 9–13 in methanol with a broad band of UV light centered at 350 nm in a Rayonet reactor afforded 2‐cyclopentenone derivatives 15–19 in moderate to excellent yields, whereas irradiation of 14 in methanol gave phenol 8 along with other unidentified products. Irradiation of 11–14 in benzene yielded substituted phenols. The plausible reaction pathways for the product formation are discussed.
Pauson-Khand reaction of activated olefins
作者:Mohammed Ahmar、Frédéric Antras、Bernard Cazes
DOI:10.1016/s0040-4039(99)01069-2
日期:1999.7
The cobalt-mediated Pauson-Khand reaction of alkynes with electron deficient olefins was shown to be promoted by N-methylmorpholine oxide at 0-20 degrees C and led to 5-functionalized cyclopent-2-enones. (C) 1999 Elsevier Science Ltd. All rights reserved.