Perhydroazulenes. 7. Effect of a tert-Butyl Substituent at C-6 upon the Properties of the 4-Keto Derivatives

Article abstract of DOI:10.1021/jo00363a003

The four diastereoisomeric 6-tert-butyl-4-ketoperhydroazulenes 4,6,8, and 10 have been prepared.The previously unknown cis-syn isomer 6 was characterized with spectra, an analysis, and a crystal structure of its oxime.The two stereoisomeric enol acetates 11 and 12 were prepared and each isomer was used to generate the corresponding lithium enolate 13 or 16.In each case methylation of one of these enolates formed a monoalkylated product containing more than 90percent of the cis-fused isomer 14 or 17.The alkylated products were characterized by spectra, analyses, and crystal structures.The probable conformations for the enolates and the alkylated products are discussed.