CATALYTIC HYDRATION OF TERMINAL ALKENES TO PRIMARY ALCOHOLS

Direct catalytic hydration of terminal alkenes to primary alcohols would be an inexpensive route to industrially useful alcohols and a convenient synthetic route for the synthesis of terminal alcohols in general. The reaction between trans-PtHCl(PMe//3)//2 (where Me equals CH//3) and sodium hydroxide in a one-to-one mixture of water and 1-hexene yields a species that, at 60 degree C and in the presence of the phase-transfer catalyst benzyltriethylammonium chloride, catalyzes selective hydration of 1-hexene to n-hexanol at a rate of 6. 9 plus or minus 0. 2 turnovers per hour. Hydration of 1-dodecene to n-dodecanol occurs at a rate of 8. 3 plus or minus 0. 4 turnovers per hour at 100 degree C. Deuterium labeling experiments with trans-PtDCl(PMe//3)//2 show that hydration involves reductive elimination of a C-H bond. At low hydroxide concentrations ( less than 8 equivalents), hydration of the water-soluble olefin 3-butene-1-ol to 1,4-butanediol exhibited a first-order dependence on hydroxide concentration for loss of catalytic activity. This suggests that hydroxide attacks the coordinated alkene slowly.