Hydroamination and Hydroaminoalkylation of Alkenes by Group 3–5 Elements: Recent Developments and Comparison with Late Transition Metals Jérôme Hannedouche, Emmanuelle Schulz To cite this version: Jérôme Hannedouche, Emmanuelle Schulz. Hydroamination and Hydroaminoalkylation of Alkenes by Group 3–5 Elements: Recent Developments and Comparison with Late Tran- sition Metals. Organometallics, American Chemical Society, 2018, 37 (23), pp.4313-4326. 10.1021/acs.organomet.8b00431. hal-02391895 HAL Id: hal-02391895 https://hal.archives-ouvertes.fr/hal-02391895 Submitted on 27 Aug 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Hydroamination and Hydroaminoalkylation of Alkenes by Group 3– 5 Elements: Recent Developments and Comparison with Late Tran- sition Metals Jérôme Hannedouche*†‡ and Emmanuelle Schulz*†‡ †Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182, Université Paris-Sud, Rue du Doyen Georges Poitou, Orsay, F-91405, France, ‡ CNRS, Orsay, F-91405, France. ABSTRACT: This short review highlights recent catalyst developments from Group III to V elements reported in the last few years to promote two highly atom-saving transformations, namely the hydroamination and hydroaminoalkylation, for the synthesis of both cyclic and acyclic nitrogen-containing compounds. A specific emphasis is given to reports leading to scalemic compounds essentially via intramolecular hydroamination catalyzed by Groups III-IV metals and intermolecular hydroaminoalkylation cata- lyzed by Group V elements. In both transformations, performances of these electropositive metals will be compared with recent developments obtained through late transition metals catalysis. tion order will appear essentially to propose a rather historical 1. INTRODUCTION and mechanistic outlook. Very recent examples for Hydroamination1 and hydroaminoalkylation2 reactions are enantioselective hydroamination or hydroaminoalkylation two transformations giving rise to the formation of structurally reactions promoted by transition metals will also be introduced varied nitrogen-containing cyclic or acyclic compounds, use- for a comparison of the successes and lacks of both types of ful as bulk or specialty chemicals. They have known a huge transformations. development in the last thirty years. Whereas the first reaction implies the addition of an N-H bond of an amine across a C-C multiple bond, the second is characterized by the addition of 2. ASYMMETRIC HYDROAMINATION the α-C-H bond of an alkylamine across C-C unsaturation. 2.1 Introduction Numerous elements from the periodic table have been demon- strated active to promote these transformations; this short Since the seminal work of the Marks’ group reporting the review lists and comments on recent developments obtained first asymmetric alkene hydroamination reaction catalyzed by with the use of elements from the Groups III, IV and V. Nu- C1-symmetric chiral ansa-lanthanocene complexes, intensive merous elements from the periodic table have been demon- research efforts over the last 25 years have been devoted to the strated active to promote these transformations; this short development of chiral rare-earth metallocene and non- review lists and comments on recent developments obtained metallocene complexes to tackle the challenges associated with the use of elements from the Groups III, IV and V., high- with this highly atom-economic transformation, namely, the lighting common features between the two historically related control of both reaction regioselectivity (Markovnikov and reactions in terms of catalyst structures and mechanistic as- anti-Markovnikov) in a highly enantioselective fashion. Alt- pects. hough various players of the field have made some significant contributions in this area,1a,f the major breakthrough in terms Moreover, as non-toxic and readily available species, these of reaction rates, enantioselectivity and versatility arose from elements as catalysts allow direct transformations of the group of Hultzsch with the disclosure, in 2006, of the unactivated olefins or amine derivatives, and thus perfectly synthesis of rare-earth alkyl complexes (Ln = Sc, Y, Lu) sur- match the concept of green chemistry for atom-economy reac- rounded by C -symmetric chiral 3,3’-bis[tris(aryl)silyl]- tions. Herein will be more specifically developed reports pub- 2 substituted binaphtholate ligands, such 1 (Scheme 1, left), and lished in the last few years, dealing with the hydroamination their catalytic applications in alkene hydroamination.3a These or hydroaminoalkylation of unactivated alkene derivatives, complexes are to date amongst the most active and and the authors advise to refer to excellent previous reviews 1,2 stereoselective rare-earth catalysts for the on the topics for former articles. A particular emphasis will cyclohydroamination of a variety of aminoalkenes (ee’s up to be placed on complexes that allow enantioselective catalysis, 95 and 61% for 5- and 6-membered rings respectively). Late- which however does not exist for all elements, until now. This ly, they have demonstrated their ability to promote the asym- review will be divided according to the reaction type and the metric Markovnikov intermolecular hydroamination of prima- Group; however, within a reaction type, a different presenta- ry aliphatic amines and aliphatic alkenes with high ly reported C2-symmetric binol-derived complexes, certainly enantioselectivity (51-61% ee) as the unique example of rare- due to the presence of the additional amine in the ligand earth-catalyzed asymmetric intermolecular hydroamination framework as suggested by the authors. Contributions in the reaction.3b In the context of metallocene hydroamination cata- area of chiral rare-earth non-metallocene complexes are also 6 7 lysts, worth noting is the key contribution of the group of be gained by the groups of Livinghouse and Ward using C2- Sadow that reported, in 2011, a very active and symmetric complexes derived from chiral N-substituted enantioselective, non-epimerizable C1-symmetric, binaphthylamine and bis(oxazolinylphenyl)amide (BOPA) cyclopentadienylbis(oxazolinyl)borate yttrium catalyst such 2 ligands respectively. These systems still require improvements (Scheme 1) for the formation of various gem-disubstituted to compete with the Hultzsch and Sadow catalysts (1 and 2). pyrrolidines in high yields (95–100%) and enantiomeric purity Surprisingly, the major developments of the last five-years (89–96% ee).4 Mechanistic investigations suggest that these arise from chiral half-metallocene complexes, that were the state-of-the-art Group III hydroamination catalysts operate subject of much less effort in contrast to non-metallocene through distinct mechanistic pathways. As schematically de- complexes that were the main focus of the hydroamination picted in Scheme 1, cyclohydroamination reactions catalyzed community. In 2014, the group of Yang reported the synthesis yttrium complexes 1 and 2 are proposed to proceed by a step- of a novel chiral silicon-linked tridentate amido-indenyl ligand wise -insertive pathway (involving migratory 1,2-alkene from indene and enantiopure 1,2-cyclohexanediamine and its insertion into the Y-N -bond followed by aminolysis at the structurally-defined yttrium bis(trimethylsilyl)amido complex 8 thus generated Y-C -bond) and a concerted proton-assisted 3 (Scheme 2, top). As catalyst at low loading, this complex is non-insertive pathway (evolving concomitant C–N/C–H bond efficient for the formation of various gem-disubstituted formation at an yttrium amido-/amino-alkene species via a pyrrolidines and piperidines in high conversion and high ee multi-center-transition state) respectively. These mechanisms values from primary amines tethered to monosubstituted al- have found echo in other related metal-catalyzed kenes or styrene-type alkenes (Scheme 2, top). It is worth hydroamination reactions. Despite these advances, there is still noting that this constrained geometry complex provides some a need for improvement as these systems suffer from some of the highest ee values to date, 97% and 72%, for the for- moderate stereoselectivity and/or require a large excess of mation of a five-membered ring and a six-membered ring alkene under forcing reactions conditions. Efforts that have respectively in the field of rare-earth-catalyzed been conducted in this direction in the last five years using hydroamination. The high enantioinduction observed may chiral metallocene and non-metallocene catalysts will be high- result from the presence of three chiral elements in the com- lighted below, as well as those involving chiral late-transition plex as revealed by solid-state characterization, although epi- metal elements for comparison. merization of the chiral planarity may not be excluded in the catalytic conditions as suggested by X-ray analysis of the Scheme 1. State-of-the-art Group III catalysts for asym- erbium congener. metric alkene hydroamination and proposed operating mechanisms. Scheme 2. Selected Group III chiral complexes for asym- metric intra-