Catalytic promotion of piperonyl alcohol to trimethylendioxyorthocyclophane by bentonitic earth, or by hydrochloric acid

The cyclooligomerization of piperonyl alcohol (1) afforded trimethylendioxy orthocyclophane (2), a novel product, which was promoted by the catalytic a ction of a commercial bentonitic earth, Tonsil Actisil FF, as well as by hy drochloric acid in 1, 4-dioxane. The structure of 2 was established by H-1, C-13 NMR and HMQC experiments (DMSO-d(6) and in the solid state), and by t he corresponding mass spectrometric data (EI, GLD and HR). (C) 1999 Elsevie r Science B.V. All rights reserved.