Application of microwave spectroscopy to the mechanism of hydrogen-deuterium exchange in propene by homogeneous catalysts

Quantitative microwave analyses of [2H1]propenes formed by deuterium exchange of propene with CH3OD by homogeneous catalysts of platinum, rhodium, and nickel are reported. The results permit a clear choice of the metal hydride addition–elimination mechanism over the π-allyl mechanism. Secondary isotope effects in the β-elimination of MH from the intermediate 1 -deuterio-2-metallo-propane are in good agreement with a calculated value of kH/kD= 1·18. The relationship of the propene results to deuteriation/isomerization studies on but-1-ene is discussed.