PROCESS FOR THE PREPARATION OF COMPOUNDS OF THE MEGASTIGMAN-SERIES, AND INTERMEDIATES FOR THIS SYNTHESIS

1. A process for the preparation of a compound of the magastigmane series of the formula I see diagramm : EP0102531,P21,F1 where R**1 is hydrogen or methyl and the broken line can represent a further C-C bond, wherein A) the novel 1-formyl-2,6,6-trimethyl-3-oximidocyclohex-1-ene of the formula II see diagramm : EP0102531,P21,F2 is converted in a conventional manner by Grignard reaction with allymagnesium chloride, allylmagnesium bromide, proplymagnesium chloride, or propylmagnesium bromide or by Grignard reaction with propynylmagnesium chloride or propynylmagnesium bromide and subsequeuent partial hydrogenation of the triple bond in the side chain or, however, by reaction with acetone in the presence of an alkaline catalyst and subsequent reduction of the carbonyl group in the side chain to a hydroxyl group or subsequent Grignard reaction with methylmagnesium chloride or methylmagnesium bromide to a novel alcohol of the formula III see diagramm : EP0102531,P21,F3 wherein R**2 is see diagramm : EP0102531,P21,F4 or see diagramm : EP0102531,P21,F5 and B) the resulting alcohol of the formula III is heated at from 90 to 120 C, in the presence of water and of a sparingly volatile strong acid.