Jian-Bo Feng

Palladium‐Catalyzed Carbonylative Cyclization of Arenes by CH Bond Activation with DMF as the Carbonyl Source

A novel palladium-catalyzed CO-gas- and autoclave-free protocol for the synthesis of 11H-pyrido[2,1-b]quinazolin-11-ones has been developed. Quinazolinones, which are omnipresent motif in many pharmaceuticals and agrochemicals, were prepared in good yields by C-H bond activation and annulation using DMF as the CO surrogate. A (13) CO-labelled DMF control experiment demonstrated that CO gas was released from the carbonyl of DMF with acid as the promotor. The kinetic isotope effect (KIE) value indicated that the C-H activation step may not be involved in the rate-determining step. This methodology is operationally simple and showed a broad substrate scope with good to excellent yields.

A general and practical oxidation of alcohols to primary amides under metal-free conditions

A general procedure for oxidation of both benzyl alcohols and alkyl alcohols to primary amides under catalyst free conditions has been developed. 34 examples of primary amides were produced from their corresponding alcohols in moderate to excellent yields. This is a practical procedure for primary amides synthesis; water and tert-butanol are the only by-products. A commercial drug, Piracetam, was prepared in one step with 73% yield as well.

The first zinc-catalyzed oxidation of sulfides to sulfones using H2O2 as green oxidant

An interesting procedure for the oxidation of sulfides to sulfones has been developed. By using a catalytic amount of zinc salt as the catalyst, DBU as the ligand, various sulfones were produced in good yields with hydrogen peroxide as the terminal green oxidant. Note that this is the first example of zinc-catalyzed oxidation of sulfides to sulfones.

Base-promoted synthesis of dibenzoxazepinamines and quinazolinimines under metal-free conditions

An interesting base-promoted protocol for the synthesis of dibenzo[b,f][1,4]oxazepin-11-amines and quinazolinimines has been developed. Started from commercially available 2-fluorobenzonitriles, 2-aminophenols and 2-aminoethanol, good to excellent yields of the corresponding heterocycles can be achieved. Notably, only K3PO4 or K2CO3 was required as the promoter here and the reaction can be easily performed on a large scale.

KOtBu-promoted synthesis of multi-substituted 4-aminopyrimidines from benzonitriles and aliphatic amides

Multi-substituted 4-aminopyrimidines have been prepared from commercially-available benzonitriles and aliphatic amides under transition-metal-free conditions. With KOtBu as the only promoter, the desired pyrimidines were isolated in moderate to excellent yields.

Synthesis of quinazolinimines and quinazolinamines from 2-fluorobenzonitriles under catalyst-free conditions.

A convenient procedure for the synthesis of quinazolinimines and quinazolinamines from 2-fluorobenzonitriles has been developed. By using KO(t)Bu as the promotor with 2-aminopyridines or amidines as the reaction partner, the desired heterocycles were produced in moderate to good yields under catalyst-free conditions.