Aryne generation vs. Truce-Smiles and fries rearrangements during the Kobayashi fragmentation reaction: a new bi-aryl synthesis

Abstract

Treatment of (ortho-trimethysilyl)aryl phenylsulfonates with a soluble fluoride source initiates a Truce-Smiles rearrangement leading to the formation of functionalized bi-aryls. This new carbon-carbon bond-forming reaction proceeds without recourse to transition metal catalysis, under mild reaction conditions and with good functional group compatibility.

Radical Truce-Smiles reactions on an isoxazole template: Scope and limitations

“…These radical Truce-Smiles rearrangements are also promoted by other reducatns such as Cu(NO 3 ) 2 -Cu 2 O and efforts are currently underway in order to define agents which promote cyclization without the intervention competing side reactions. Anionic variants 42 of the Truce-Smiles rearrangements were unsuccessful when using an isoixazole nucleus as acceptor.…”

“…Purified by column chromatography afforded the title compound as a white crystal; Yield 60 mg (22 %). (2-Bromophenoxy)trimethylsilane 42 In an oven dried flask, 2-bromophenol (57.09 mmol, 9.7 g, 6.5 mL, 1 eq.) in anhydrous THF (15 mL) was stirred at rt under nitrogen atmosphere.…”

Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates

“…In this case, N-methyl sulfonamides were the elective substrates albeit a part of the tether is maintained in the final structure. This is common even for other related metal-free biaryl syntheses exploiting the Truce-Smiles rearrangement in aryl sulfonamides and aryl phenylsulfonates [44][45][46] or the [3,3]-sigmatropic rearrangement of sulfonium salts arising from the reaction of aryl sulfoxides and phenols [47]. To overcome this problem, the use of a metal catalyst (mainly Ni) was mandatory as reported for the real extrusion of CO in diaryl ketones [48,49] or of SO 2 in diaryl sulfones (Scheme 1c) [50].…”

Modern Aspects of the Smiles Rearrangement

“…Truce–Smiles rearrangements of aryl anion equivalents to form biaryls are quite rare in the literature . An elegant example was recently reported by Quayle, who observed a Truce–Smiles rearrangement during their preparation of potential benzyne precursors 82 (Scheme ) . The TBAF‐mediated de‐silylation of nitrobenzene sulfonate esters resulted in a desulfonative rearrangement of the aryl anion equivalent to afford biaryl phenols 83 .…”