One-pot, solvent-free Pd(II)-catalyzed direct β-C-H arylation of carboxamides involving anhydrides as substrates via in situ installation of directing group

A Guide to Directing Group Removal: 8‐Aminoquinoline

“…The Babu group have had some success with in situ installation of the AQ directing group and functionalization in one pot, followed by AQ removal from the crude product prior to purification (Scheme 6 A). [47–49] While this strategy may be more time‐efficient since it only requires one purification step, yields are not yet comparable to the traditional three‐step DG installation—functionalization—DG removal protocol with purification after each step (Scheme 6 B).…”

Sustainable C–H functionalization under ball-milling, microwave-irradiation and aqueous media

“…In 2019, Babu and co-workers came up with a Pd( ii )-catalyzed direct β-C–H arylation of carboxamides involving symmetrical anhydrides as substrates, in solvent-free conditions, via in situ installation of a bidentate directing group (Scheme 41). 89 Instead of taking the longer route of installation of a DG (DG = directing group), a one-pot multi-component reaction pathway was chosen to make the process step-economical. To optimize, they heated a mixture of butyric anhydride, 8-aminoquinoline, m -tolyl iodide, the catalyst Pd(OAc) 2 (10 mol%) and AgOAc, the additive (2.2 equiv.)…”

“…This type of C–H functionalization work with undirected or non-directed groups or without a DG in neat conditions would overcome the limitations of the DG-approach (which was the case for Babu et al ’s work 89 ) leading towards greenness by reducing waste, avoiding derivatives to reduce reaction steps etc .…”

“…88 Scheme 41 Pd(II)-catalyzed C-H arylation of anhydrides in neat medium by Babu et al. 89 Ni/NHC catalyst loading (0.3 mol%), the group demonstrated the addition product in 85% yield with high catalyst turn-over number (TON = 283).…”

Step-Economical C–H Activation Reactions Directed by In Situ Amidation

“…Recently, the same group further investigated the in situ amidation-mediated C-H activation of the C(sp 3 )-H bonds in alkyl amides by employing anhydrides as the C-H bond donors. 27 As outlined in Scheme 7, the reactions of anhydrides 21, AQ and aryl iodides were conducted in the presence of Pd(OAc) 2 and AgOAc. Compared with the reactions employing acyl chlorides, milder heating at 100°C allowed the reactions to proceed smoothly.…”