Synfacts 2021; 17(04): 0427
DOI: 10.1055/s-0040-1706718
Metals in Synthesis

Directed ortho-Lithiation of Benzamides

Contributor(s):
Paul Knochel
,
Andreas Hess
de Silva SO, Reed JN, Snieckus V. * University of Waterloo, Canada
Directed Lithiation of N,N-Diethylbenzamides. Regiospecific Synthesis of Contiguously Tri- and Tetra-Substituted Alkoxybenzenes.

Tetrahedron Lett. 1978;
51: 5099-5102
DOI: 10.1016/S0040-4039(01)85822-6.
 

Significance

Snieckus and co-workers reported a regiospecific ortho-lithiation of various N,N-diethylbenzamides using sec-BuLi and TMEDA in THF. The formed lithiated species were trapped with a range of electrophiles and the desired products were obtained in moderate to excellent yield.


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Comment

The authors demonstrated the utility of this methodology for the synthesis of naturally occurring alkaloids. Thus, a formylated product was converted by successive reduction and cyclization into meconine in 90% yield. Subsequent hydrolysis furnished opianic acid in 50% yield.


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Publication History

Publication Date:
18 March 2021 (online)

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