SYNTHETIC APPLICATION 19 closure of 2-(Y,Y-dimethylallyl)-phenol gives only the chroman LXVIII, irrespective of the presence or absence of peroxides. 29 Treatment of 2-allylphenols with mercuric salts gives mercurimethyl--CHCH 2 HgX LXIX LXX dihydrobenzofurans such as LXIX. 79-80 ' 81 The halomercuri group can be replaced by iodine by treatment with potassium iodide, and this is a method of preparing iodo compounds like LXX. Another occasionally useful transformation of allylphenols is the isomerization to propenylphenols by strong alkali, as in the well-known isomerization of eugenol to isoeugenol. For example, 2-methoxy-6-allylphenol (LXXI) is changed to the propenyl compound LXXII by OH LXXI LXXII heating 1 part of the phenol with 2 parts of powdered potassium hydrox-ide and 1 of water for one hour at 170°.* This isomerization also can be brought about by heating with soda lime without solvent/ but the phenolic hydroxyl must be etherified. 64
This is the end of the preview. Sign up
access the rest of the document.