Mechanism of catalytic isotope exchange in alcohols promoted by early-transition-metal alkoxides. Comment on the paper by Nugent and Zubyk

Nugent and Zubyk recently reported separate /alpha/- and /beta/- exchange processes for scrambling H - D in alcohols in the presence of various M/sub x/(OEt)/sub y/ (M = Zr, X = 1, y = 4; M = Nb, Ta, x = 2, y = 10) complexes at temperatures from 180 to 220/degree/C. This same reaction appears relevant to the mechanism of higher alcohol synthesis from syngas under metal oxide catalysts. An intermediate in the reaction path is an /eta//sup 3/-enolate. An interpretation of the data of Nugent and Zubyk offers indirect evidence for the existence of the /eta//sup 3/-enolate, which has been substantiated by reports from other laboratories. 22 refs.