Based on the above mechanistic studies and control experiments, the proposed mechanism of this reaction is shown below (Figure ). First, as reported by Li et al., 8 X -(X = Br or I) is oxidized to Br2 or I2 by anodic oxidation. Subsequently, the resulting Br2 or I2 reacts with PPh3, and the Appel reaction proceeds in the presence of alcohol as substrate. The alcohol substrate is then converted to the Mitsunobu intermediate 89 to give the alkyl halide 90. The resulting alkyl halide 90 undergoes XAT (halogen atom transfer) through the Fe complex to form the radical intermediate 91. 91 reacts readily with the Michael acceptor to form 92, which is then derivatized by SET (single electron transfer) to give the desired product 93 (path A). The Fe n species produced after XAT and SET are expected to be converted to Fe n-1 by cathodic reduction and used in the next catalytic cycle. The process of 92 to 93 may also be mediated by the HAT (hydrogen atom transfer) mechanism (path B) in addition to the SET mechanism (path A).