Catalytic Hydration of Terminal Alkenes to Primary Alcohols
CRAIG M. JENSEN 1 and
WILLIAM C. TROGLER 1
1 Department of Chemistry, D-006, University of California at San Diego, La Jolla, CA 92093.
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(PMe3)2 (where Me = CH3) and sodium hydroxide in a one-to-one mixture of water and 1-hexene yields a species that, at 60°C and in the presence of the phasetransfer catalyst benzyltriethylammonium chloride, catalyzes selective hydration of 1-hexene to n-hexanol at a rate of 6.9 ± 0.2 turnovers per hour. Hydration of 1-dodecene to n-dodecanol occurs at a rate of 8.3 ± 0.4 turnovers per hour at 100°C. Deuterium labeling experiments with trans-PtDCl(PMe3)2 show that hydration involves reductive elimination of a C—H bond. At low hydroxide concentrations (<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. At high hydroxide concentrations, the rate of catalysis was hydroxide-independent and first order in alkene. Substitution of coordinated water (k1 = 9.3 ± 0.5 x 10-3 liters per mol per second) appears to be limitng under these conditions.
Submitted on December 9, 1985
Accepted on April 15, 1986
