Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

Abstract

SummaryA Fe(acac)3-catalyzed decarboxylative coupling of 2-(aryl)vinyl carboxylic acids with cycloalkanes was developed by using DTBP as an oxidant through a radical process. This reaction tolerates a wide range of substrates, and products are obtained in good to excellent yields (71–95%). The reaction also shows excellent stereoselectivity, and only trans-isomers are obtained.

Metal‐Free Preparation of Cycloalkyl Aryl Sulfides via Di‐tert‐butyl Peroxide‐Promoted Oxidative C(sp3)H Bond Thiolation of Cycloalkanes

“…Based on the above results and literature reports,4,10,13 a possible mechanism for the cycloalkane thiolation reaction is illustrated in Scheme , which includes a key radical oxidative coupling step. At the beginning, homolysis of DTBP gives tert ‐butoxy radical intermediate A under the conditions of heating.…”

“…both for activating the C( sp 3 )H bond of cycloalkanes and subsequent coupling to form CY (Y=O, N, C) bonds 9. Recently, our group also developed an Fe‐catalyzed decarboxylative alkenylation of cycloalkanes via a radical process 10. The metal‐free C( sp 3 )H bond functionalization progress for C( sp 2 )C( sp 3 ) bond formation of heteroaromatics and cycloalkanes promoted by DTBP has also been reported (Scheme c) 11,12.…”

“…[9] Recently, our group also developed a Fe-catalyzed decarboxylative alkenylation of cycloalkanes via a radical process. [10] The metal-free C(sp 3 )–H bond functionalization progress for C(sp 2 )–C(sp 3 ) bond formation of heteroaromatics and cycloalkanes promoted by DTBP have also been reported (Scheme 1c). [11,12] To the best of our knowledge, no reports for the construction of C–S bond through C(sp 3 )–H bond functionalization of cycloalkanes are described.…”

Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

“…The pioneering works were focused on the cross-dehydrogenative coupling (CDC) reactions of alkanes, which were reported by Li and other groups [ 11 – 15 ]. Recently, several types of reactions with alkanes as substrates have been developed, such as the Minisci reaction with heteroarenes [ 16 – 17 ], radical addition to unsaturated bonds [ 18 – 19 ], decarboxylative alkenylation of cycloalkanes with aryl vinylic carboxylic acids [ 20 – 21 ], trifluoromethylthiolation [ 22 ], thiolation [ 23 – 24 ], alkenylation [ 25 – 26 ], dehydrogenation−olefination and esterification [ 27 – 28 ], radical addition/1,2-aryl migration [ 29 ], cascade alkylation-initiated cyclization [ 30 – 31 ] and other radical reactions [ 32 – 34 ]. Due to their low polarity and high bond-dissociation energy, the functionalization of unactivated sp 3 C–H bonds in simple alkanes remains as a challenging task.…”

Iron‐Promoted Radical Reactions: Current Status and Perspectives

“…Han, Pan, and co-workers reported the addition of cycloalkane radicals to 2-(aryl)vinyl carboxylic acids 24, promoted by Fe(acac) 3 (20 mol %) in the presence of di-tert-butylperoxide (Scheme 22). [48] Av ariety of substituted cinnamic acid derivatives were employed under the optimized reaction conditions, which were found to tolerate avariety of functional groups on the aromatic ring. Heterocyclic substrates were also compatible and the reactionw as possible with other cycloalkanes, such as cyclopentane, cycloheptane, and cyclooctane, thereby affording the corresponding products (59)i nh igh yields.…”