N,N-Dimethylformamide-stabilized palladium nanoclusters as a catalyst for Larock indole synthesis

Abstract

Pd NCs serve recyclable and highly active catalyst to indole synthesis.

Recent Progress in the Transition Metal Catalyzed Synthesis of Indoles

“…During the drafting of this review many papers continued to appearing in the literature. They have been not discussed here but they could be of interest for the reader [147][148][149][150][151][152][153][154][155][156][157][158][159]. Recently, the classical syntheses, which are still widely used and improved, have been juxtaposed with many transition metal catalyzed syntheses.…”

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

“…DMF-stabilized Pd nanoclusters in a catalytic amount (3 mol%) were reported by Obora et al for Larock indole ligandfree synthesis using o-haloanilines (6k) and symmetrical and asymmetrical alkynes (48d, Scheme 171) in DMF at 135 C. 309 They synthesized the Pd-nanoclusters via the reduction of PdCl 2 with DMF following their previously reported protocols. 310 The catalyst was recycled three times with a slight loss in activity, yielding 80%, 68%, and 63% of 88n (R 1 , R 2 ¼ H; R 3 , and R 4 ¼ Ph) in three consecutive cycles due to the leaching of the metal catalyst (ICP).…”

Recent Uses of N,N-Dimethylformamide and N,N-Dimethylacetamide as Reagents

“…In addition, DMF can act as stabilizing agent of metal colloids to afford effective and recyclable catalysts, based for examples: on iron for the hydrosilylation of alkenes (Equation (103)) [ 109 ], on palladium for the synthesis of 2,3-disubstituted indoles from 2-halooanilines and alkynes (Equation (104)) [ 110 ], on copper for Sonogashira–Hagihara cross-coupling reactions (Equation (105)) [ 111 ], on iridium for methylation of alcohols (Equation (106)) and amines (Equation (107)), using methanol as the C1 source [ 112 ]. …”

“…on palladium for the synthesis of 2,3-disubstituted indoles from 2-halooanilines and alkynes (Equation (104)) [ 110 ],…”