Mechanistic Impact of Oxime Formation Accompanying 1,3-Dipolar Cycloadditions of Nitrile Oxides
نویسندگان
چکیده
Benzonitrile oxide (la) reach with 1,1,2,2,3,3-hexamethyl-4,5-bis(methylene)cyclopen~e (5) to give a mixture of the 1,3-dipolar cycloaddition product 8 and the oxime 9. This reaction is 26 times slower than the corresponding reaction of la with 1,2-bis(methylene)cyclopentane (15), which exclusively yields the 2-isoxazoline 19. With the assumption that the oxime 9 is generated by a stepwise process, one can estimate that the barrier for the concerted cycloaddition of la with 15 is approximately 2 kcal/mol lower than the barrier for the formation of an intermediate.
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