ON THE CONSTITUTIONAL STABILITY OF ETA(1)-ALLYLMETAL COMPOUNDS

Many eta(1)-allymetal species undergo a rapid haptotropic rearrangemen t. The stereochemical outcome of reactions of these allylmetal species with aldehydes depends on whether the haptotropic rearrangement is fa ster or slower than the reaction with the aldehyde. We present here a test system based on kinetic resolution, by which just this informatio n becomes available. Thus, haptotropic rearrangement of cyclohexenylli thium, -magnesium chloride, -titanium triisopropoxide, and -titanium t etraisopropoxide, was found to be faster than addition to the aldehyde 9. Borotropic rearrangement in cyclohexenyldiethylborane was found to be slower than the addition to the aldehyde 9.