The selective alkylation reaction of guaiacol (1) with camphene (2) over H-Mordenite has been studied, through which the content of 5-isocamphylguaiacol (3a) among the alkylation products terpenylguaiacols (3～6) has been raised to about 25.0% . The subsequent hydrogenation and hydrogenolysis of the obtained alkylation products give a mixture of terpenylcyclohexanols containing 23.0% of trans-3-isocamphylcyclohexanol which is the essential constituent of "Santalydol". Five main peaks on gas chromatography of the alkylation products have been identified by IR, ^1H NMR and MS .

Key words: SELECTIVITY, ALKYLATION, MORDENITE, CAMPHENE, GUAIACOL