Efficient, highly regioselective fries rearrangements of methyl 3-(2-acyloxy-4-methoxyphenyl)propanoates: The first total syntheses of the linear acylated coumarins geijerin and dehydrogeijerin.
作者:Nicholas Cairns、Laurence M. Harwood、David P.pp]Astles
DOI:10.1016/s0040-4039(00)80285-3
日期:1988.1
Aluminiumchloridecatalysed para-Fries rearrangement of methyl 3-(2-acyloxy-4-methoxyphenyl)propanoates (5)in nitromethane furnishes the corresponding 5-acylated products (6) cleanly and in high yield. The rearrangement products may be converted into 6-acyl-7-methoxycoumarins (2) including the naturally occurring geijerin (2a) and dehydrogeijerin (2b).