Some months ago we conducted follow-up studies on the trimethylchlorosilane(TMSCl)/methylaluminoxane(MAO)/2,4,4-trimethyl-1-pentene (TMP) modeling reaction, this time using ²⁹Si NMR spectroscopy.  ¹H NMR appeared to support addition of silicenium ion to TMP; however, ²⁹Si showed that instead silyl halide undergoes ligand exchange type reactions with MAO and that polymerization is initiated in an ill-defined manner by this process.  Our group will be submitting a paper on this soon and the purpose of this announcement is to alert the reader to the fact that the chemistry described previously for this initiator system is incorrect.