A new and efficient hypervalent iodine-benzyne precursor, (phenyl) [o-(trimethylsilyl)phenyl]iodonium triflate: Generation, trapping reaction, and nature of benzyne

A new and efficient hypervalent iodine-benzyne precursor, (phenyl) [2-(trim ethylsilyl)phenyl] iodonium triflate (10), is reported. The hypervalent iod ine-benzyne precursor 10 is readily prepared by reaction of 1,2-bis(trimeth ylsilyl)benzene with a PhI(OAc)(2)/TfOH reagent system. Treatment of 10 wit h Bu4NF in CH2Cl2 at room temperature gives high yields of the benzyne addu cts in the presence of a trapping agent such as furan, 2-methylfuran, anthr acene, tetraphenylcyclopentadienone, or 1,3-diphenylisobenzofuran. Especial ly, the result of the reaction in the presence of furan indicates a quantit ative generation of benzyne and its efficient capture by the furan. Similar ly, methylbenzynes (22 and 27) are efficiently generated from the correspon ding methyl-substituted (trimethylsilyl)phenyliodonium triflates (12 and 13 ). The preparation of the hypervalent iodine-benzyne precursors, the genera tion of benzynes, the trappings reactions, and the nature are described in detail together with the advantages of the present reagents over the previo usly reported benzyne precursors.