NMR investigations on boron complexes in the conjugate addition on alpha,beta-unsaturated imides.

G Cardillo, L Gentilucci, M Gianotti, A Tolomelli

Index: Org. Lett. 3(8) , 1165-7, (2001)

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Abstract

[reaction: see text]. The 1,4-addition of O-benzylhydroxylamine to alpha,beta-unsaturated imide 1 in the presence of BF3.Et2O proceeds with the preferential attack of the nucleophile on the Cbeta-re face. To explain this unexpected reactivity 1H, 13C, and 11B NMR investigations have been carried out on the boron-imide complex, which show the presence of an S-cis imide chain conformation.