Ozonolysis of the ethylene acetals of 2-substituted 2-cyclohexenones followed by cyclization of the intermediate 1,6-dicarbonyl compounds affords 6-substituted 7-formyl-1,4-dioxaspiro[4,4]non-6-enes in modest yields. The same procedure applied to protected 2-substituted 2-cyclohexenols gives 2-substituted 3-formyl-2-cyclopentenyl 2-methoxyethoxymethyl ethers in satisfactory yields.
2-取代的2-
环己烯酮的
乙烯缩醛的
臭氧分解,随后对中间体1,6-二羰基化合物进行环化,能够以适度的产率得到6-取代的7-
甲醛-1,4-二氧杂螺[4,4]九烯-6-烯。同样的步骤应用于保护的2-取代
2-环己烯醇时,可以令人满意的产率得到2-取代的3-
甲醛-2-
环戊烯基2-甲氧基乙氧甲基醚。