Rhodium‐HMPT‐Catalyzed Direct ortho Arylation of Phenols with Aryl Bromides.

Abstract

Polyphenyl derivatives Polyphenyl derivatives Q 0700Rhodium-HMPT-Catalyzed Direct ortho Arylation of Phenols with Aryl Bromides. -Various phenols undergo direct o-arylation with phenyl bromides under optimized conditions to give mono-and diarylated products. A mechanism, involving the formation of aryl phosphites as key intermediates from the phenols and HMPA is proposed. -(OI*, S.; WATANABE, S.-I.; FUKITA, S.; INOUE*, Y.; Tetrahedron Lett. 44 (2003) 48, 8665-8668; Dep. Mater. Chem., Grad. Sch. Eng., Tohoku Univ.,

Transient Directing Groups for Transformative C–H Activation by Synergistic Metal Catalysis

“…The reaction procedure was further simplified with the aid of commercially available P(NMe 2 ) 3 as the catalytic modifier to generate the phosphinite transient DG, which was independently developed by Oi, Inoue, and co-workers. 19,20 Further studies by Bedford and co-workers showcased that another commercially available reagent, namely i-Pr 2 PCl, also proved viable as a co-catalytic modifier for rhodium-catalyzed C-H arylation of phenols. 21,22 Recently, Ye and co-workers applied this strategy to devise an efficient approach to 3,3 0 -diaryl BINOLs 8 by C-H arylation of BINOLs 7 with aryl bromides 5 (Scheme 5B).…”

Modular bismacycles for the selective C–H arylation of phenols and naphthols

“…While 1-naphthol is a poor substrate for both established Bi(V) reagents (48% with BiPh5) 28 and metal catalyzed C-H functionalization (38-43% with 5 mol% Rh at T ≥ 100 °C), 24,25,26 it is arylated efficiently using our protocol (26, 86%). The contrast between our results and those of Barton 28 are especially striking, and again highlight the enhanced reactivity conferred by Suzuki's sulfone-bridged bismacycle scaffold.…”

“…For example, cross-coupling typically requires challenging ortho-selective halogenation or borylation of the hydroxyarene, 13 whereas C-H functionalization demands installation and subsequent removal of Lewis-basic directing groups. Pioneering approaches that entirely avoid additional directing groups 21,22,23 -or that allow the in situ installation and removal of co-catalytic directing groups 21,24,25,26 -represent an almost ideal solution to the problems of step-and atom-efficiency, but suffer from practical limitations such as moderate scope and poor selectivity. In addition to potential issues surrounding step count, the extant cross-coupling and C-H arylation strategies rely on activation of a carbon-halogen bond, which results in chemoselectivity issues for polyhalogenated substrate combinations.…”

“…Arylation of meta-substituted phenols has not been adequately explored in either the extant bismuth 60,64 or C-H functionalization 24,25,26 literature, but typically occurs with low regioselectivity.…”

Phenol-Directed C–H Functionalization

“…110 A similar strategy was also reported by Oi and Inoue, who employed hexamethylphosphorus triamide (HMPT) as a more readily available cocatalyst. 111 More recently, this strategy was also adopted by Ye for the rapid derivatization of BINOL. 112 In addition to ortho-C−H arylation, significant efforts have been directed to related ortho-C−H allylation reactions (Scheme 24).…”