Chlorotrifluoromethylation of Terminal Olefins by Atom Transfer‐Type Radical Reaction Catalyzed by Cobalt Complexes

Abstract

A cobalt porphyrin‐catalyzed chlorotrifluoromethylation reaction of olefins is described. The use of CF3SO2Cl as the CF3 radical source and a cobalt catalyst enabled the selective addition of CF3 radicals under thermal conditions. Various functional groups such as esters and Ar–X moieties, which can be reactive with low valent transition metal catalysts, were well‐tolerated in this catalytic process. A highly functionalized alkaloid derivative was also tolerated as a substrate. As a demonstration of the bio‐inspired catalytic system, catalytic usage of vitamin B12, which is the commercially available form of the natural cobalt porphyrinoid, was employed, and diastereoselective chlorotrifluoromethylation of the alkaloid molecule was achieved.

C–C Bond Forming Reactions Enabled by Vitamin B12─Opportunities and Challenges

“…Some bromides, however, gave intermediates prone to subsequent reactions, furnishing dehalogenated product 47 or cyclopropane 48 (Scheme B). Unactivated olefin 49 has also been explored in related studies on chlorotrifluoromethylation (Scheme C) . Although most substrates were converted using the cobalt­(II) porphyrin complex (CoClTPP), vitamin B 12 was also compatible with this transformation, and when used with an alkene derived from cinchona alkaloids, a higher diastereoselectivity was observed compared to the CoClTPP-catalyzed reaction (6.4:1 vs 1.4:1).…”

Mn(OAc)3-Mediated Addition Reactions of NaSO2CF3 and Perhalogenated Carboxylic Acids with Unactivated Alkenes Conjectured by a Single Electron Transfer and Halogen Abstraction Mechanism

“…13 C­{ 1 H} NMR (126 MHz, CDCl 3 ) δ 165.9, 133.7, 129.9, 129.3, 128.7, 125.2 (q, 1 J (C, F) = 277.2 Hz), 66.8, 50.4 (q, 3 J (C, F) = 3.0 Hz), 39.4 (q, 2 J (C, F) = 29.4 Hz). 19 F NMR (376 MHz, CDCl 3 ) δ −63.7 (t, 3 J (F, H) = 10.1 Hz) …”

“…19 F NMR (376 MHz, CDCl 3 ) δ −63.7 (t, 3 J(F, H) = 10.1 Hz). 25 ((5-Chloro-7,7,7-trifluoroheptyl)oxy)benzene (3e). Following the general procedure for halotrifluoromethylation described in this experiment, 1e (0.50 mmol, 88.1 mg) reacted to 3e (78.6 mg, 56% yield, light yellow oil), which was purified by silica gel chromatography (PE/EA = 250:1).…”

Recent Advances on the Halo- and Cyano-Trifluoromethylation of Alkenes and Alkynes

“…More recently, Matsubara and coworkers studied the chlorotrifluoromethylation of substituted terminal olefins in the presence of highly coordinated square-planar cobalt(II) complexes, such as cobalt(II) porphyrin catalysts CoTPP (TPP= 5,10,15,20-tetraphenylporphyrinato) [ 33 ]. After checking various cobalt and copper complexes, it was found that the combination of CoClTPP and CF 3 SO 2 Na was the most efficient catalyst when the reaction was carried out in MeCN as solvent.…”