Directed ortho-Metalation of Arenesulfonyl Fluorides and Aryl Fluorosulfates

Studies on directed ortho -metalation (DoM) of arenesulfonyl fluorides (ArSO (2) F) with in situ electrophile trapping are presented. Under optimized conditions (LDA, THF, -78 degrees C), a series of model substrates was mono- and difunctionalized with trimethylsilyl chloride in good yields. The synthetic results reveal powerful directing character of the SO (2) F group, being ahead of bromine and methoxy substituents. Under the same metalation conditions, aryl fluorosulfates (ArOSO (2) F) display fragmentation to arynes and migration of the SO (2) F group to the ortho position (anionic thia-Fries rearrangement).