Allylation of 1,4-Benzoquinones

Simple, direct and regioselective allylation of 1,4-benzoquinones is an important objective in the synthesis of many isoprenoid quinones such as plastoquinone-1 and vitamin Ki, which play important roles in cellular metabolism and photosynthesis. In a new procedure where the use of a strongly coordinating solvent was found to play an important role, it was shown that reaction of 3 equivalents of (3-methyl-2-butenyl)trifluorosilane with one equivalent of 2,3-dimethyl-l,4-benzoquinone in formamide in the presence of 5 equivalents of FeCl3.6H20 for 23 hours at 40°C gave plastoquinone-1 1, in 90% yield. 

Give a mechanistic interpretation for this transformation which takes into account the probable role of the solvent. 

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