Synthesis of Five- and Six-Membered Heterocycles Through Palladium- Catalyzed Reactions

Green synthesis of pyrazole systems under solvent-free conditions

“…The protonation of this intermediate by compound (1) led to the formation of a positively charged ion (7) that acts as a Michael acceptor. Therefore, the adduct (7) immediately undergoes Michael-type addition with anion of the NH-acid (8) to generate the open-chain intermediate (9). Finally, the ketenimine intermediate (9) can be converted to target molecule by intramolecular N-cyclization reaction.…”

“…Nitrogen-containing heterocyclic compounds are widespread in nature, and their applications to biologically active pharmaceuticals, agrochemicals and functional materials are becoming more and more important (2)(3)(4)(5)(6). Thus, the development of new and efficient synthetic methods for N-heterocycles with structural diversity is one of the major interests of modern synthetic organic chemists (7)(8)(9). The interest in five-membered systems with two adjacent nitrogen atoms stems from the occurrence of saturated and partially saturated pyrazoles in biologically active compounds and natural products (10,11).…”

Sequentially Palladium-Catalyzed Processes in One-Pot Syntheses of Heterocycles

“…The use of ortho-iodo anilines provides access to a variety of substrates for consecutive domino reactions which can then be applied to the synthesis of heterocycles [5][6][7]9,[48][49][50][51] and functional materials [39]. One example is the preparation of (tetrahydroisobenzofuran) spiro-benzofuranones or spiro-indolones in moderate to excellent yields by use of the domino insertion-coupling-isomerization-intramolecular Diels-Alder sequence of alkynoyl ortho-iodo phenolesters or alkynoyl ortho-iodo anilides and propargyl allyl ethers [52,53].…”

“…A particular advantage of OPEN ACCESS these concepts is the huge increase in structural complexity facilitated by the use of even the simplest starting materials. This is also one of the driving factors for constant research advancements in this field [5][6][7][8][9][10][11][12][13][14][15][16][17].…”

One-pot multi-component green synthesis of highly substituted piperidines

“…The development of new and efficient methods for the synthesis of N-heterocycles is one of the greater interests of modern synthetic organic chemistry. [3][4][5] Synthesis of complex heterocyclic molecules can be easily achieved starting from readily available starting materials in a single step multi-component reactions (MCRs). 6 In most of the cases these reactions are advantageous over the linear step-wise syntheses because of the operational simplicity, shorter reaction time, ecological concerns, low processing costs and avoidance of protection and deprotection processes.…”