OPENING OF THE EPOXIDE BRIDGE IN 3a,6-EPOXYISOINDOL-1-ONES BY THE ACTION OF BF₃·Et₂O IN ACETIC ANHYDRIDE

Abstract

The opening of the epoxide bridge in N-substituted 2,3,7,7a-tetrahydro-3a,6-epoxyisoindol-1-ones by the action of BF₃·Et₂O in acetic anhydride at 25°C over 1 h proceeds through an S_N1 mechanism. The allylic type cation formed in the first step is stabilized by the addition of an acetoxy group at C-5 in the isoindole system to give a mixture of cis and trans isomers of 5,6-diacetoxy-2,3,5,6,7,7a-hexahydroisoindol-1-ones, which are aromatized under these conditions over 24 h to give 2,3-dihydro-1H-isoindol-1-ones.

Authors: F. I. Zubkov, V. P. Zaytsev, E. S. Puzikova, E. V. Nikitina, V. N. Khrustalev, R. A. Novikov, and A. V. Varlamov.

English Translation in Chemistry of Heterocyclic Compounds, 2012, 48 (3), pp 514-524

http://link.springer.com/article/10.1007/s10593-012-1024-0