The Stereochemistry of Nucleophilic Addition. IV. The Condensation of 2,2,6-Trimethylcyclohexanone with t-Butyl Acetate in the Presence of Lithium Amide

The stereochemistry of the condensations of 2,2,6-trimethylcyclohexanone with t-butyl acetate in the presence of lithium amide, with ethyl bromoacetate in the presence of zinc (Reformatsky reaction), and with ethylmagnesium iodide (Grignard reaction) was studied. The configurations of the products in these reactions were assigned on the basis of their chromatographic behavior, and on the basis of spectroscopic and chemical studies of them. From the present experiments it is evident that all of these nucleophilic addition reactions proceed in a similar fashion. Further, the treatment of t-butyl 1-hydroxy-2,2,t-6-trimethyl-r-1-cyclohexaneacetate (IIa) with potassium hydrogensulfate or with dilute sulfuric acid gave (±)-cis-tetrahydroactinidiolide (IX), which was isolated from the essential oil of cigar tobacco leaves by Kaneko and Hoshino, while the treatment of IIa with isopropenyl acetate in the presence of p-toluenesulfonic acid gave a mixture of IX and its trans-isomer (X).