摘要:
The organometallic radicals COCP2 (1) and CpFe(HMB) (HMB = C6Me6; 2) react with the radical-clock reagent 5-hexenyl iodide to give unrearranged addition products, while with cyclopropylmethylhalides both unrearranged cyclopropylmethyl and rearranged 3-butenyl addition products are formed. The rate constant for radical addition was estimated from the product ratios. For 1 a lower bound of k2 greater-than-or-equal-to 5.8 X 10(8) s-1 at 67-degrees-C was obtained, while for 2 a value of k2 = (1.2 +/-0.2) X 10(9) s-1 at 25-degrees-C was determined. Thus, both 1 and 2 are extremely efficient radical scavengers.