|
[摘要]:Double Br-Li exchange and sequential trapping of the dilithio intermediate with different electrophiles gives unsym. substituted (hetero)arenes in a 1-pot fashion. E.g., reaction of 2,5-dibromothiophene with nBuLi/TMEDA/THF/-78?followed by addn. of TMSCl/THF and then DMF followed by warming to room temp. to give 61% yield of 5-(trimethylsilyl)thiophene-2-carbaldehyde. |
|