Templated deprotonative metalation of polyaryl systems: Facile access to simple, previously inaccessible multi-iodoarenes

Abstract

Building blocks for pharmaceutical/electronic materials have been prepared using a templated C–H bond–breaking approach.

s-Block cooperative catalysis: alkali metal magnesiate-catalysed cyclisation of alkynols

“…Since rst reported by Wittig in 1951, 1 alkali metal magnesiates have evolved from mere curiosities to a new family of versatile organometallic reagents which nds widespread applications in organic synthesis. [2][3][4][5][6][7] By engaging metal-metal cooperativities, these bimetallic systems can offer superior chemo-and regioselectivities and/or functional group tolerances to those of their monometallic counterparts. 8 Most reactivity studies have focused on using these reagents as metallating reagents (via Mg-H or Mg-X exchange processes) as well as anionic transfer agents to unsaturated organic molecules.…”

Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities

“…This powerful method relies on the azametallo ring scaffold, which can override acidity criteria and direct remarkable selective and regiospecific polymetallations. For example ortho–meta“ or meta–meta” di‐metallations of substituted arenes and anilines (Scheme ) have been accomplished, whereas reactions with the polyaryl substrate para ‐terphenyl result in di‐ or even tetra‐metallated substrates …”

“…For example ortho-meta" or meta-meta" di-metallations of substituted arenes and anilines (Scheme 1) [31] have been accomplished, whereas reactions with the polyaryl substrate para-terphenyl result in di-or even tetra-metallated substrates. [32] Surprisingly,c ompared to the established mono-and bimetallic metallationchemistry of tertiaryamines, analogous studies based on tertiaryp hosphines are relativelys carce. Given the synthetic utility of phosphorus-based ligandsi nc atalyst design, [35] material chemistry and the stabilisation of main group and transition-metal complexes [36] investigation of their functionalisation and reactivity is of special importance.I nc ontext to synthetic medicinalc hemistry,a lkali metal amide complexes feature prominently, [37] while relatedp hosphorus containing compounds have been generally overlooked.…”

Trans‐Metal‐Trapping: Concealed Crossover Complexes En Route to Transmetallation?

“…Illustrating that the base structure can overcome D o M, selective meta , meta“ dimagnesiation takes place with substrates such as N , N ‐dimethylaniline and tert‐ butylbenzene, when reacted with [Na 4 Mg 2 (TMP) 6 n Bu 2 ] . Remarkably, the polyaryl substrate para ‐terphenyl could be deprotonated twice on one terminal Ph ring to generate mono‐inverse‐crown, [Na 4 Mg 2 (TMP) 6 (3,5‐ para ‐terphenyl‐di‐ide)], or four times (twice on each terminal Ph ring) to afford bis‐inverse‐crown [{Na 4 Mg 2 (TMP) 6 } 2 (3,3′′,5,5′′‐ para ‐terphenyl‐tetra‐ide)] (Scheme ) …”

“…[24] Remarkably,t he polyaryl substrate para-terphenyl could be deprotonated twice on one terminal Ph ring to generatem ono-inversecrown,[ Na 4 Mg 2 (TMP) 6 (3,5-para-terphenyl-di-ide)], or four times (twiceo ne ach terminal Ph ring) to afford bis-inverse-crown [{Na 4 Mg 2 (TMP) 6 } 2 (3,3'',5,5''-para-terphenyl-tetra-ide)] (Scheme 7). [25] Te mplate metallation offers applicabilityi ns ynthetic campaignsw here twofold metallation is required for onward functionalisation. This was nicely illustrated through conversion of biphenyl to [Na 4 Mg 2 (TMP) 6 (3,5-biphenyl-di-ide)],w hichf ollowing iodolysis and Cu-catalyzed Ullmann-typecoupling of carbazole generates 3,5-bis(N-carbazolyl)-1,1'-biphenyl (Scheme 8), of interestino rganic light-emitting diode technology.…”