N-Benzoylamides of 2,2,6,6-tetramethylpiperidine are not ortholithiated by organolithium compds. but instead undergo nucleophilic addn. of the organolithium compd. to the arom. ring in the manner of a conjugate addn. The resulting dearomatized enolates may be protonated or alkylated, and yield substituted cyclohexadienes in yields of up to 76%. Deprotection of the piperidine ring is possible under
Carbolithiation of aromatic rings: cyclohexadienes from N-aroyl-2,2,6,6-tetramethylpiperidines
作者:Jonathan Clayden、Yann J. Y. Foricher、Ho Kam Lam
DOI:10.1039/b206479k
日期:2002.9.11
Benzamides whose nitrogen atom is part of a 2,2,6,6-tetramethylpiperidine ring are dearomatised by alkyllithiums, which attack them regioselectively to yield, after electrophilic quench, substituted cyclohexadienes.