Palladium-catalyzed unactivated β-methylene C(sp³)–H bond alkenylation of aliphatic amides and its application in a sequential C(sp³)–H/C(sp²)–H bond alkenylation

Abstract

A palladium(II)-catalyzed β-methylene C(sp(3))-H bond alkenylation of acyclic aliphatic amides with alkenyl halides has been developed. Both (E)-olefins and (Z)-olefins can be readily accessed using this method and a possible (Z)/(E)-olefin isomerization pathway is proposed. A solvent effect-promoted sequential C(sp(3))-H bond alkenylation and C(sp(2))-H bond alkenylation was also studied, and can provide a convenient route to novel diene compounds.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“…Access to linear E -olefins from E -iodo alkenes and Z -isomers from Z -olefins was obtained, albeit with moderate E / Z ratios in the latter case ( Scheme 81A ). 485 …”

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

“…Daugulis and co-workers first observed that 8-aminoquinoline amides can serve as ad irecting group for this purpose, whereby a b-methylene CÀHbond of amide 101 is arylated to afford 102 (Scheme 17). [14] Thei ncorporation of various functional groups at these CÀHb onds has been rendered possible as ar esult of the contributions of different research groups.For the formation of C À Cbonds,the alkylation of 103, the alkynylation of 106,a nd the alkenylation of 109 and 101 were developed by the groups of Daugulis, [49] Tobisu and Chatani, [50] Chen, [51] and Rao, [52] respectively.The geometry of vinyl iodide 110 is preserved in Chenss ystem during the alkenylation of amide 109.…”

Pd-catalysed ligand-enabled carboxylate-directed highly regioselective arylation of aliphatic acids

“…However, the substrate scope was limited to aliphatic acids with a β-quaternary centre, due to the well-known Thorpe–Ingold effect in cyclopalladation17, and ratios of mono- to diarylated products in the range 2.5:1 to 5:1 were observed. Thus, the use of various directing groups to achieve regioselective β-C( sp 3 )–H bond functionalization of carboxylic acid derivatives18192021222324252627282930313233343536373839404142434445 has been extensively explored in the past decades (Fig. 1).…”

“…In the same year, Daugulis reported the well-known bidentate directing group 8-aminoquinoline, which has been demonstrated to have excellent ability in assisting β-C( sp 3 )-H arylation of carboxylic acids20. Since then, a number of β-C( sp 3 )-H functionalization reactions, such as arylation212223, alkenylation24, alkylation2526, alkynylation2728, alkoxylation29, amination30 and so on3132333435, employing various transition metal catalysts, have been developed. Inspired by the assisting ability of 8-aminoquinoline, researchers developed a series of N , N -bidentate directing groups for site-selective C( sp 3 )–H bond functionalization in aliphatic acids, which provided various approaches in the synthesis of important synthetic units (Fig.…”