Beta'-Lithiation of Alpha, Beta-Unsaturated Amides

The novel (beta)'-lithiation of (alpha)-alkyl-(alpha),(beta)-unsaturated secondary and tertiary amides is reported. N-Methyl-1-cyclohexenecarboxamide and N-methyl-1-cyclopentenecarboxamide are metalated at nitrogen and at the (beta)'-carbon with either sec-butyllithium/TMEDA at -78(DEGREES)C or n-butyllithium at 0(DEGREES)C. Further reaction with a variety of electrophiles leads in good yield to the (beta)'-substituted products. Similarly, lithiation of N,N-diisopropyl-1-cyclohexenecarboxamide by sec-butyllithium/TMEDA at -78(DEGREES)C followed by treatment with electrophiles affords the (beta)'-substituted tertiary amides. N-Methyl-3-ethyl-2-methyl-2-pentenamide and (E)-N-methyl-2-methyl-2-butenamide also undergo exclusive (beta)'-metalation. However, deprotonation occurs at the (gamma)-position in N-methyl-2-ethyl-3-methyl-2-butenamide, in which the cis-(gamma)-carbon is less highly substituted than the (beta)'-carbon. The acyclic amides afford unsymmetrical allylic anions, which react with electrophiles to give mixtures of isomeric products. The dianion from N-methyl-4-t-butyl-1-cyclohexenecarboxamide is deuterated non-selectively but reacts with benzophenone to give only the diastereomer which results from addition cis to the t-butyl group. The reactions of the lithiated amides with aldehydes show only a slight erythro selectivity.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Kempf, Dale John

• Chemistry, Organic

Identifier

(UMI)AAI8302907

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70197