Aziridination of alkenes using 2-substituted-3-acetoxyamino-quinazolin-4(3H)-ones:: changes in transition state geometry resulting from addition of trifluoroacetic acid or by an electron-withdrawing 2-substituent

The effects of TFA on the competitive reactions of 3-acetoxyaminoquinazolinones 2 and 10 with methyl acrylate and with tert-butyl acrylate are interpreted as supporting a change in transition state geometry from one where (Q) C=O/ (ester)C=O overlap 7b is replaced by (Q)C=N+H/(ester)C=O overlap 7c (Q = quinazolinone). Aziridinations of methyl or tert-butyl acrylate using 2-trifluoromethyl-substituted 3-acetoxyaminoquinazolinones:20 and 21 take place with (Q) C=N/(ester)C=O overlap;22 even in the absence of TFA.