| abstract |
Perhydro-5,5-8a-trimethyl-2-naphthalenone is prepared by acid cyclization of carboxylic esters of formula <IMAGE> (II) having a double bond in one of the positions indicated by the dotted lines and wherein symbol R designates a C1-C6 alkyl radical, X stands for a monovalent radical of formula P(O)(OR1)2 or C(O)R2, R1 represents a C1-C6 alkyl group and R2 is either a linear or branched alkyl group or a substituted or unsubstituted phenyl radical, and wherein the wavy line represents a C-C bond of cis or trans configuration, or of formula R are defined as above, and R0 represents a C3-C6 alkyl radical, preferably branched, followed by basic decarboxylation of the obtained product. |