Treatment of β-(1-ethoxycarbonyl-2-keto-3-methylcyclohexyl)-propionaldehyde with concentrated sulphuric acid furnishes not only the expected ethyl 5-methylbicyclo[3:3:1]non-3-en-9-one-1-carboxylate (II),but also two rearranged products,7-methylindan-4-carboxylic acid (VI) and ethyl 2-acetylbicyclo[3:3:0]oct-1(2)-ene-5-carboxylate(IX).
用浓
硫酸处理β-(1-乙氧基羰基-2-酮基-3-甲基环己基)-
丙醛不仅提供了预期的乙基5-甲基双环[3:3:1] non-3-en-9-one-1 -
羧酸盐(II),还有两个重排产物,7-甲基
茚满-4-
羧酸(VI)和2-乙酰基双环[3:3:0] oct-1(2)-烯-5-
羧酸盐(IX) 。