80767-57-3Relevant academic research and scientific papers
Condensation limonene-xylenons en presence de resines cationiques : obtention de (dimethyl-benzo)-1,2 bicyclooxonannes-3
Pottier, Eliane
, p. 335 - 339 (2007/10/02)
During studies on terpene-phenol condensations catalyzed by cation exchange resins, we had noticed the unusually low rate of formation of resin-like heavy products in the reaction of limonene with phenols.We had then shown the presence of aromatic tricyclic ethers not reported so far in this type of reaction.In the first place we endeavoured to elucidate the strutures of the chromans formed from cresols.Results published about the same time showed us that the compounds we obtained were very similar to certain phenols formed in the synthesis of cannabinoids.While considering the material advantages of catalysis by ion exchange resins, we decided to extend this study to that of the reactions of limonence with dimethylphenols.We could thus determine precisely the stereochemistry of chromans.These ring ethers are of two types, A and B (fig. 1.).In all cases, the substituent at position 7 is trans with respect to the aromatic ring.The study of the rates of ring ethers and resin-like phenolic products thus obtained indicates competition between the reactions of formation of these compounds.Ring ethers form essentially when steric constraint at the para position hinders substitution at that position and hence subsequent formation of polycondensation products.On the other hand, in the ortho substitution which takes place then, the steric problem is, to a great extent, solved by the formation of tricyclic compounds.
