1,2-Bis(arylthio)arene synthesis via aryne intermediates

Abstract

Use of a bulky LDAM base allows for an efficient synthesis of 1,2-bis(arylthio)arenes from aryl halides and triflates.

Gram-Scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles

“…Di-(1-adamatyl)amine and (1-adamantyl)cyclohexylamine were synthesized according to reported procedure. 39…”

“…Synthesized according to the same procedure 39 (3 d at 240 °C) using 1-bromoadamantane (1.29 g, 6 mmol) and 1-cyclohexylamine (1.19 g, 12 mmol). After cooling to r.t., the resulting solid was crushed with a spatula, and aqueous NaOH (25 mL, 20% w/v) and DCM (50 mL) were added.…”

“…34 Although preparation of amides by acyl substitution with lithium amide bases in esters and activated amides was extensively explored by Szostak, 35 36 the methodology was not demonstrated for the preparation of sterically hindered N , N -disubstituted systems. Therefore, we tested reactions of nonenolizable acyl fluorides 37 with lithium amide bases of gradually increasing size of substituents at the nitrogen atom: LiHMDS and LDA (named group I , Scheme 4 ), lithium tert -butylisopropylamide and LiTMP (group II ), and very crowded derivatives of adamantylamine 38 (LiAd(cH) and LiNAd 2 39 ) and bis-(2,6-xylidyl)amine (LiN(2,6-xyl) 2 , group III ). Results of the studies are summarized in Scheme 4 .…”

“…More crowded representatives of group II also led to a series of products 3f – p , 40 except for reaction with the most demanding 1-adamantanecarbonyl fluoride ( 2e ). 41 The lithium salt of 1-adamantylcyclohexylamine (LiNAd(cH), group III ) with PhCOF led to the formation of amide 3r in only 16%, and, finally, the most hindered LiNAd 2 39 and LiN(2,6-xyl) 2 failed to give the expected amides at all. 42 However, when the latter aromatic lithium amide underwent Friedel–Crafts type benzoylation at the para -position of the 2,6-xylidine ring on warming the reaction mixture to room temperature ( 3s , 56%), LiNAd 2 consumed benzoyl fluoride even at low temperature (–78 °C), but produced polar, ill-defined oligomeric product.…”

Palladium-catalyzed direct C–H thiolation of 2-pyridyl sulfoxide with disulfides

“…Very recently, Daugulis and co-workers have reported base promoted reaction of in situ generated arynes with disulfides in the synthesis of symmetrical 1,2-bis(arylthio)benzenes. 19 The ring-opening reaction of thianthrene with lithium metal affords o -arylsulfinyl thiophenol. 20…”