Abstract Acid catalysed dehydration of the diols 5, derived from the cyclohexenone 3 affords mixtures of 8 and 11. The product ratio 8/11, although strongly dependent on both the reaction conditions and the substituent R, is independent of the diol configuration; this indicates a cationic intermediate 6. Conditions were found, which allow the sequence A [RIGHTWARDS ARROW] B [RIGHTWARDS ARROW] C [RIGHTWARDS ARROW] D ( ...
