Alkylation and Oligomerization of the Lithium Enolate of 2-Norbornenones. Stereochemical Consequences of Enolate Aggregation

Article abstract of DOI:10.1021/jo00372a021

Alkylation of the lithium enolate of norbornenone in THF with alkyl halides gave a single trimeric oligomer containing one alkyl group as the major product.The structure of this diastereomer has been determined by 1H and 13 2-D NMR techniques and analysis of relaxation times.Direct reaction in the aggregated enolate with the Zimmerman-House-Jackman cubic structure is implied.Compounds with a 7-anti substituent could be alkylated in satisfactory yield.The use of the dimethylhydrazone anion as an enolate equivalent gave good yields of 3-alkylnorbornenones (methyl, n-hexyl, benzyl). 1H and 13C NMR data for products and intermediates are reported.