An Efficient Three-Component One-Pot Approach to the Synthesis of 2,3,4,5-Tetrahydro-1H-2-benzazepines by Means of Rhodium-Catalyzed Hydroaminomethylation

Palladium-Catalyzed [5 + 2] Rollover Annulation of 1-Benzylpyrazoles with Alkynes: A Direct Entry to Tricyclic 2-Benzazepines

The first Pd-catalyzed [5 + 2] rollover annulation of 1-benzylpyrazoles with alkynes to assemble 10H-benzo[e]pyrazolo[1,5-a]azepines (tricyclic 2-benzazepines) has been developed. The rollover annulation implies a twofold C-H activation of aryl and heteroaryl C_sp²-H bonds (C-H/C-H) of 1-benzylpyrazoles (five-atom partners) and alkynes to give the [5 + 2] annulated compounds.

Relay Zn(ii)- and Au(i)-catalyzed aziridination/cyclization/ring expansion sequence to form 3-benzazepine derivatives

The synthesis of 3H-benzo[d]azepine-2-carboxylates from 2-alkynylphenyl aldimines and α-diazo esters using Zn(ii) and Au(i) catalysts is described.

Efficient synthesis of chiral γ-aminobutyric esters via direct rhodium-catalysed enantioselective hydroaminomethylation of acrylates

The first successful rhodium catalysed asymmetric hydroaminomethylation of alkenes using a single catalyst is reported with ees up to 86%.

Metal-free aza-Claisen type ring expansion of vinyl aziridines: an expeditious synthesis of seven membered N-heterocycles

A metal-free approach for the synthesis of 7-membered aza-heterocycles has been developed by the intermolecular [5 + 2] cycloaddition of non-activated vinylaziridines and alkynes. This method has a broad substrate scope under mild reaction conditions to afford structurally diverse 7-membered N-heterocycles in high yield up to 92%.

Recent progress in rhodium-catalyzed hydroaminomethylation

This review covers the recent studies featuring the development of catalysts for alkene hydroaminomethylation.

Recent advances in catalytic C-N bond formation: a comparison of cascade hydroaminomethylation and reductive amination reactions with the corresponding hydroamidomethylation and reductive amidation reactions

The design and catalytic implementation of tandem reactions to selectively create nitrogen-containing products under mild conditions has encountered numerous challenges in synthetic chemistry. Several known classes of homogeneously catalyzed carbon-nitrogen bond formation including hydroamination, hydroamidation, hydroaminoalkylation, hydroaminomethylation and reductive amination were reported in the literature. More recently, a new class of C-N bond formation consisting of hydroamidomethylation and reductive amidation extended the applicability of these synthetic methodologies. The tandem reactions do considerably impact on the selectivity and efficiency of synthetic strategies. This review highlights and compares selected examples of the hydroaminomethylation, reductive amination, hydroamidomethylation and reductive amidation reactions, and thus consequently reveals their potential applications in synthetic chemistry as well as chemical industries.

Rhodium-catalyzed hydroaminomethylation of cyclopentadiene

The substance class of amines is highly relevant for chemical and pharmaceutical industries. A one-step rhodium catalyzed direct route from cyclopentadiene to saturated C₆-amines is presented via hydroaminomethylation.

Rhodium-catalyzed regioselective hydroaminomethylation of terminal olefins with pyrrole-based tetraphosphorus ligands

A protocol was developed to prepare linear amines by regioselective hydroaminomethylation of terminal olefins with pyrrole-based tetraphosphorus ligands. The reactivity of the ligand is modulated by the substituent of the biphenylphosphane moiety, with ligand L5 exhibiting the highest reactivity.

Rhodium-catalyzed hydroformylation in fused azapolycycles synthesis

N-Heterocycles, including fused ones, have proven to be an important class of compounds since they possess biological and pharmacological activities themselves and serve as valuable intermediates for synthetic drug discovery. My interest in the synthesis of these compounds stems from studies dealing with the hydroformylation (oxo) of olefins. The dihydroindolizines and benzofused ones are easily generated via rhodium-catalyzed hydroformylation of N-allylpyrroles and indoles: the butanal intermediate undergoes an intramolecular cyclodehydration giving the final polycyclic compound. This chapter reports my results in the area of the conversions of oxo aldehydes with additional C,C-bond-forming reactions together with relevant work from other laboratories on additional C,N-bond-forming reactions, encountered in the field of Azapolycycles synthesis over the last 5 years or so. The intramolecular sequences for polycylization will be especially emphasized using rhodium complexes to effect these transformations, under both conventional and microwave heating.

Synthesis of oxindoles by tandem Heck-reduction-cyclization (HRC) from a single bifunctional, in situ generated Pd/C catalyst

A tandem sequence involving palladium-catalyzed sequential Heck-reduction-cyclization transformations in mild conditions has been developed for the synthesis of oxindoles. The protocol involves inexpensive reagents and does not require any additives such as base or ligands.

Heterogeneous multifunctional catalysts for tandem processes: an approach toward sustainability

The development of sustainable organometallic chemistry is one of the many challenges that chemists must address to solve environmental issues. Until now, the classical approach was to develop highly selective homogeneous catalysts for a single transformation. However, a new area of research focuses on the execution of two or more reactions in the same vessel using heterogeneous multitask catalysts. This approach results in a reduced number of operations leading to time and cost benefits. Moreover, owing to the scarcity of natural resources and the recent dramatic cost increase of these resources and metals, the development of recyclable heterogeneous catalysts is urgent. This Minireview focuses on the latest developments in tandem reactions promoted by heterogeneous multitask catalysts.