A New and Efficient Hypervalent Iodine−Benzyne Precursor, (Phenyl)[o-(trimethylsilyl)phenyl]iodonium Triflate:  Generation, Trapping Reaction, and Nature of Benzyne

Abstract

A new and efficient hypervalent iodine−benzyne precursor, (phenyl)[2-(trimethylsilyl)phenyl]iodonium triflate (10), is reported. The hypervalent iodine−benzyne precursor 10 is readily prepared by reaction of 1,2-bis(trimethylsilyl)benzene with a PhI(OAc)2/TfOH reagent system. Treatment of 10 with Bu4NF in CH2Cl2 at room temperature gives high yields of the benzyne adducts in the presence of a trapping agent such as furan, 2-methylfuran, anthracene, tetraphenylcyclopentadienone, or 1,3-diphenylisobenzofuran. Especially, the result of the reaction in the presence of furan indicates a quantitative generation of benzyne and its efficient capture by the furan. Similarly, methylbenzynes (22 and 27) are efficiently generated from the corresponding methyl-substituted (trimethylsilyl)phenyliodonium triflates (12 and 13). The preparation of the hypervalent iodine−benzyne precursors, the generation of benzynes, the trapping reactions, and the nature are described in detail together with the advantages of the present reagents over the previously reported benzyne precursors.

Efficient and General One‐Pot Synthesis of Diaryliodonium Triflates: Optimization, Scope and Limitations

“…[5,6] Their use in copper-and palladium-catalyzed cross-coupling reactions allows milder reaction conditions than in couplings with aryl halides. [7][8][9] Furthermore, diaryliodonium salts are used to generate benzynes [10] and serve as photo-initiators in polymerizations. [9,11] Symmetrical diaryliodonium salts are generally preferable to unsymmetrical salts in arylation reactions.…”

Efficient One‐Pot Synthesis of Bis(4‐ Tert ‐Butylphenyl) Iodonium Triflate

“…8 Synthetic routes to diaryliodonium salts typically involve 2-3 steps. 4,9 Preformed inorganic iodine(III) reagents can be employed to make symmetric salts.…”

Palladium‐Catalyzed Formation of Highly Substituted Naphthalenes from Arene and Alkyne Hydrocarbons

“…203-204 8C; the 1 H NMR spectrum was identical to that reported in the literature. [38] General procedures for preparation of naphthalenes from an arene 1 and an alkyne 2:…”