2/7-Azirine alcohol inversion

The absolute reaction rate of methyl acrylate and the nitrile ylide derived from 2,3-diphenyl-2/f-azirine at 25°C has been estimated as 7.6 X 10 AT sec. Inductive effects exerted by substituents on the nitrile ylide also have an important effect on the regioselectivity of the cycloaddition. Benzonitrilio-hexafluoro-2-propanide (44) and methyl acrylate yield products with inverse regioselectivity as compared with the reactions of the related benzonitrilo-2-propanide 47. The difference in regioselectivity has been attributed to the larger coefficient at the trisubstituted carbon atom of the gem-trifluoromethyl substituted nitrile ylide 44. This result parallels the different mode of addition of alcohols to nitrile ylides 44 and 47. 

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See also in sourсe #XX -- [ ]

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