Cation radicals. III. Sterically hindered chlorinating agents

Synthesis of Trialkylamines with Extreme Steric Hindrance and Their Decay by a Hofmann-like Elimination Reaction

“…tert -Octylamine was obtained from TCI (Japan). The Grignard-reagents 2- exo -norbornylMgBr, EtMgBr, neopentylMgBr, cyclopentylMgBr, and t -BuMgBr were prepared from the corresponding alkyl bromide and magnesium turnings following a general literature procedure and used immediately after preparation. , Compounds 8 , 9 , 11 , 12 , 13 , 17 , 25a , , 26b , 27e , 27g , 28c , 29c-d , di- tert -butylamine, 1,1,3,3-tetramethylisoindoline, 1,1,3,3-tetraethyl-isoindoline, di- tert -amyl-amine, , tert -butyl- tert -octylamine, di-1-adamantylamine, 3,3,5,5-tetramethylmorpholin-2-one, tert -butylcyclohexylamine, 2-ethyl-1,1,3,3-tetraethylisoindoline ( 30c ), 2-isopropyl-1,1,3,3-tetraethylisoindoline ( 30d ), and N - tert -butyl- N -tritylamine ( 34 ) were prepared according to reported procedures. The NMR data of amine 40c were confirmed by the literature …”

“…1 H NMR (600 MHz, C 6 D 6 ): δ 3.31 (tt, 3 J = 11.4 Hz, 7.7 Hz, 1H, N−CH), 1.68−1.81 (m, 4H, CH 2 ), 1.54−1.61 (m, 2H, CH 2 ), 1.47−1.51 (m, 2H, CH 2 ), 1.41−1.43 (m, 6H, CH 2 ), 1.18 (s, 12H, N−C(CH 3 ) 2 ). 13 C{ 1 H} NMR (151 MHz, C 6 D 6 ): δ 59.9 (d, N−CH), 54.9 (s, N−C), 44.0 (t, CH 2 ), 33.9 (t, CH 2 ), 29.8 (q, CH 3 ), 23 4-Isopropyl-3,3,5,5-tetramethylmorpholin-2-one (32). Method A.…”

Practical and Selective sp3C−H Bond Chlorination via Aminium Radicals

“…Thec orresponding N-Cl-ammonium salts B are powerful electrophiles in classical ionic chemistry, [13] but upon judicious choice of the reaction conditions their reactivity can be diverted into radical manifolds based on aminium radicals C.These species are isoelectronic with alkyl radicals but carry aformal positive charge which dramatically enhances their reactivity towards electron rich p-systems [see Scheme 1D,p aths (a) and (b)]. [14] Pioneering work from Minisci [15] and Deno [16] has also demonstrated that these open-shell intermediates can be used in radical HAT-chlorination but required preformed N-chloroamines,H 2 SO 4 as solvent and either high-energy UV-irradiation (l = 254 nm) or an excess of FeSO 4 .Despite the potential of this reactivity mode for sp 3 C À Hf unctionalization, the harsh reaction conditions combined with the known difficulties in preparing and isolating N-chloroamines,have thwarted its adoption and exploitation by the synthetic community.…”

Sulfamate Esters Guide Selective Radical‐Mediated Chlorination of Aliphatic C−H Bonds

“…1038 8) [17] geometrically favor as even-membered-ring transition state for C À Ha bstraction. Thes ite-selectivity available through these reactions complements that achieved using traditional HLF chlorination transformations, [18] alternative guided chlorination methods, [19] or site-selective intermolecular [20] chlorination processes.…”