7731-02-4

Three unsaturated C4-bridged phospane/borane frustrated Lewis pairs (P/B FLPs) are prepared by uncatalyzed hydrophosphination of a dienylborane. The systems are bifunctional. Consequently, two examples undergo clean hydroboration reactions with

The role of structure-directing agents (SDA) in the synthesis of zeolites is investigated, and the structures obtained in the synthesis are rationalized in terms of the energetic stabilization between the SDA and the microporous zeolite structure. An explanation is provided for the synthesis outcome in terms of a balance between kinetic and thermodynamic factors throughout the nucleation and crystallization stages. The stability of β, EU-1, ZSM-11, and ZSM-12 zeolites is calculated over a wide range of Si/Al ratios when cyclohexyl alkyl pyrrolidinium salts are used as the SDA. The role of the SDA allows us to explain the final stability and the Si/Al range in which each structure can be synthesized. The stabilization of intermediate species during the nucleation is proposed to orient the final result of the synthesis. A simple kinetic model is proposed to explain the synthesis process.

The phosphorus/boron-substituted hexatriene systems 6 undergo thermally induced electrocyclic ring closure to yield the cyclohexadiene-derived P/B frustrated Lewis pairs (FLPs) 7. Subsequent TEMPO oxidation gives the phenylene-bridged FLPs 8. Both systems activate dihydrogen and the thermally robust FLPs undergo carbon-carbon coupling reactions at a mesityl group upon treatment with dimethyl acetylenedicarboxylate at elevated temperatures.

Colloidal metal nanoparticles were examined for reductive amination of phenol by ammonia under mild reaction conditions. The results showed that Rh-PVP was the most active catalyst for reductive amination reaction. Linear, cyclic, and amino alcohols were used as nucleophiles and converted to primary/secondary/tertiary amines. Using this strategy, the synthesis of an industrially important chemical, N-cyclohexyl- 2-pyrrolidone was explored.

Phenol and its derivatives, which naturally occur in lignocellulose, can be considered as a renewable feedstock not only for aromatic, but also for alicyclic compounds, such as primary and N-substituted cyclohexylamines. So far, the latter are mostly produced from non-renewable starting materials like benzene via problematic nitration/reduction or cross-coupling routes. Herein, an efficient reductive amination of phenol with ammonia or amines is demonstrated, for the first time without the need for rare and expensive noble metals and without using any additives. Various supported Ni catalysts were screened and we elucidated the influence of the key parameters, including the acid-base properties of the supporting material. Acquired knowledge was then applied to different phenol-ammonia/amine combinations, resulting in the synthesis of various primary, secondary and tertiary cyclohexylamines in fair to very high yields.

A green, efficient N-alkylation of amines with simple alcohols has been achieved in aqueous solution via an electrochemical version of the so-called "borrowing hydrogen methodology". Catalyzed by Ru on activated carbon cloth (Ru/ACC), the reaction works well with methanol, and with primary and secondary alcohols. Alkylation can be accomplished by either of two different electrocatalytic processes: (1) in an undivided cell, alcohol (present in excess) is oxidized at the Ru/ACC anode; the aldehyde or ketone product condenses with the amine; and the resulting imine is reduced at an ACC cathode, combining with protons released by the oxidation. This process consumes stoichiometric quantities of current. (2) In a membrane-divided cell, the current-activated Ru/ACC cathode effects direct C-H activation of the alcohol; the resulting carbonyl species, either free or still surface-adsorbed, condenses with amine to form imine and is reduced as in (1). These alcohol activation processes can alkylate primary and secondary aliphatic amines, as well as ammonia itself at 25-70 °C and ambient pressure.

A modular and waste-free strategy for constructing N-substituted cyclic amines via decarboxylative N-alkylation of α-amino acids employing ruthenium- and iron-based catalysts is presented. The reported method allows the synthesis of a wide range of five- and six-membered N-alkylated heterocycles in moderate-to-excellent yields starting from predominantly proline and a broad range of benzyl alcohols, and primary and secondary aliphatic alcohols. Examples using pipecolic acid for the construction of piperidine derivatives, as well as the one-pot synthesis of α-amino nitriles, are also shown.

Reductive amination of carbonyl compounds constitutes one of the most efficient ways to rapidly construct chiral and achiral amine frameworks. Imine reductase (IRED) biocatalysts represent a versatile family of enzymes for amine synthesis through NADPH-mediated imine reduction. The reductive aminases (RedAms) are a subfamily of IREDs that were recently shown to catalyze imine formation as well as imine reduction. Herein, a diverse library of novel enzymes were expressed and screened as cell-free lysates for their ability to facilitate reductive amination to expand the known suite of biocatalysts for this transformation and to identify more enzymes with potential industrial applications. A range of ketones and amines were examined, and enzymes were identified that were capable of accepting benzylamine, pyrrolidine, ammonia, and aniline. Amine equivalents as low as 2.5 were employed to afford up to >99 % conversion, and for chiral products, up to >98 % ee could be achieved. Preparative-scale reactions were conducted with low amine equivalents (1.5 or 2.0) of methylamine, allylamine, and pyrrolidine, achieving up to >99 % conversion and 76 % yield.

Piers' borane HB(C6F5)2 reacted with the alkyne Mes2P-C≡ ≡C-SiMe3 by a rarely observed 1,1-hydroboration reaction under kinetic control to give the unsaturated vicinal frustrated phosphane/borane Lewis pair 6, featuring both the PMes2 and SiMe3 groups at the same carbon atom C1. Compound 6 is a reactive P/B FLP which splits dihydrogen under mild conditions. Thermolysis at 100 °C converts it to the markedly less reactive P/B FLP regioisomer which bears the -SiMe3 substituent at carbon atom C2 adjacent to the B(C6F5)2 group. Most new compounds were characterized by X-ray diffraction.

The acetate complex Ru(OAc)2(DiPPF) (2) obtained from Ru(OAc)2(PPh3)2 (1) and 1,1′-bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc)2(CO)(DiPPF) (3) in high yield. The monocarbonyl complex 3 (0.4-2 mol %) efficiently catalyzes the N-alkylation of primary and secondary alkyl and aromatic amines using primary alcohols ROH (R=Et, nPr, nBu, PhCH2) under mild reaction conditions (30–100 °C) with an alcohol/amine molar ratio of 10-100. Formation of the monohydride RuH(OAc)(CO)(DiPPF) (4) has been observed by reaction of 3 with iPrOH in the presence of NEt3 at RT through an equilibrium reaction.

An efficient one-pot procedure for the direct reductive amination of aldehyde and ketones was achieved in the presence of sodium borohydride by using B(OSO3H)3/SiO2(SBSA) as the reusable solid catalyst in acetonitrile and solvent-free conditions. Both aromatic and aliphatic aldehyde reacted well to give the corresponding amines in excellent yields. All the products are known and well-characterized. The catalyst is recoverable and could be easily recycled by filtration and reused several times without any significant loss of its activity. SBSA acts as a dual Br?nsted/Lewis acid that is an air-stable and cost-effective solid acid. [Figure not available: see fulltext.]

This work describes the use of cheap, safe, and easy-to-handle hydrosilatrane as the reductant in direct reductive amination reactions. This efficient method enables a facile, metal-free access to secondary and tertiary amines from a wide range of aldehydes and ketones, with the synthesis of tertiary amines requiring no additives at all. This reaction demonstrates excellent functional group tolerance, chemoselectivity, and scalability. (Figure presented.).

Imine reductases (IREDs) show great potential as catalysts for reductive amination of ketones to produce chiral secondary amines. In this work, we explored this potential and synthesized the pharmaceutically relevant (R)-rasagiline in high yields (up to 81%) and good enantiomeric excess (up to 90% ee) from the ketone precursor. This one-step approach in aqueous medium represents the shortest synthesis route from achiral starting materials. Furthermore, we demonstrate for the first time that tertiary amines also can be accessed by this route, which provides new opportunities for eco-friendly enzymatic asymmetric syntheses of these important molecules.

Imine reductases (IREDs) have emerged as promising enzymes for the asymmetric synthesis of secondary and tertiary amines starting from carbonyl substrates. Screening the substrate specificity of the reductive amination reaction is usually performed by time-consuming GC analytics. We found two highly active IREDs in our enzyme collection, IR-20 from Streptomyces tsukubaensis and IR-Sip from Streptomyces ipomoeae, that allowed a comprehensive substrate screening with a photometric NADPH assay. We screened 39 carbonyl substrates combined with 17 amines as nucleophiles. Activity data from 663 combinations provided a clear picture about substrate specificity and capabilities in the reductive amination of these enzymes. Besides aliphatic aldehydes, the IREDs accepted various cyclic (C4–C8) and acyclic ketones, preferentially with methylamine. IR-Sip also accepted a range of primary and secondary amines as nucleophiles. In biocatalytic reactions, IR-Sip converted (R)-3-methylcyclohexanone with dimethylamine or pyrrolidine with high diastereoselectivity (>94–96 % de). The nucleophile acceptor spectrum depended on the carbonyl substrate employed. The conversion of well-accepted substrates could also be detected if crude lysates were employed as the enzyme source.

We herein describe a palladium-catalyzed formal aromaticity transfer coupling reaction between phenols and pyrrolidines or indolines to generate the corresponding N-cyclohexyl pyrroles or indoles. In this transformation, the aromaticity of phenols is formally passed on to the pyrrolidine or indoline units. Substituted phenols thus can serve as latent cyclohexyl equivalents for the fast construction of various N-cyclohexyl pyrroles and indoles.

Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).

The dimesitylphosphinocyclopentene/HB(C6F5)2-derived vicinal trans-1,2-P/B frustrated Lewis pair (FLP) 4 shows no direct phosphane–borane interaction. Toward some reagents it behaves similar to an intermolecular FLP; it cleaves dihydrogen, deprotonates terminal alkynes, and adds to organic carbonyl compounds including CO2. It shows typical intramolecular FLP reaction modes (cooperative 1,1-additions) to mesityl azide, to carbon monoxide, and to NO. The latter reaction yields a persistent P/B FLPNO nitroxide radical, which undergoes H-atom abstraction reactions. The FLP 4 serves as a template for the CO reduction by [HB(C6F5)2] to generate a FLP-η2-formylborane. The formylborane moiety is removed from the FLP template by reaction with pyridine to yield a genuine pyridine stabilized formylborane that undergoes characteristic borane carbaldehyde reactions (Wittig olefination, imine formation). Most new products were characterized by X-ray diffraction.

Zirconium-based frustrated Lewis pairs (FLPs) are active imine hydrogenation catalysts under mild conditions. Complexes of the type [CpR2ZrOMes][B(C6F5)4] utilize the imine substrate itself as the Lewis base component of the FLP. Catalyst performance is a function of ligand structure; in general more bulky, more electron rich cyclopentadienyl derivatives give the best results. However, Cp? derivatives are not catalytically active, being stable after initial heterolytic cleavage of H2; this allows experimental verification of the competence of the zirconocene-imine pair in FLP-type heterolytic H2 cleavage. Enamines and protected nitriles are also hydrogenated if an additional internal phosphine base is used.

Phenols can be efficiently reduced by sodium formate and Pd/C as the catalyst in water and in the presence of amines to give the corresponding cyclohexylamines. This reaction works at rt for 12 h or at 60 °C under microwave dielectric heating for 20 min. With the exception of aniline, primary, secondary amines, amino alcohols, and even amino acids can be used as nucleophiles. The reductive process is based on a sustainable hydrogen source and a catalyst that can be efficiently recovered and reused. The protocol was developed into a continuous-flow production of cyclohexylamines in gram scale achieving very efficient preliminary results (TON 32.7 and TOF 5.45 h-1).

Methyl abstraction from neutral [Cp2ZrMe(ERR)] complexes 1 (E = N, P; R, R'; = alkyl, aryl) with either B(C6F5)3 or [Ph3C][B(C6F5)4] results in the formation of [Cp2Zr(ERR′)][X] complexes 2 (X- = MeB(C6F5)3-, B(C6F5)4-). The X-ray structure of amido complexes [Cp2Zr(NPh2)][MeB(C6F5)3] (2d) and [Cp2Zr(NtBuAr)][B(C6F5)4] (2e′, Ar = 3,5-C6H3(CH3)2) is reported, showing a sterically dependent Zr/N' interaction. Complexes 2 catalyze the hydrogenation of electron-rich olefins and alkynes under mild conditions (room temperature, 1.5 bar H2). Complex 2e binds CO2, giving [Cp2Zr(CO2)(NtBuAr)]2[MeB(C6F5)3]2 (3e). Amido complex 2d reacts with benzaldehyde yielding [Cp2Zr(OCH2Ph)((OC)PhNPh2)][MeB(C6F5)3] (7d). Phosphido complex [Cp2Zr(PCy2)][MeB(C6F5)3] (2a) reacts with diphenylacetylene to yield frustrated Lewis pair [Cp2Zr(PhCCPh)(PCy2)][MeB(C6F5)3] (8a) which further reacts with a range of carbonyl substrates.

The vicinal P/B frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 undergoes 1,1-carboboration reactions with the Me3Si-substituted enynes to give ring-enlarged functionalized Csub

The invention relates to a method for producing a N-substituted amine compound by catalyzed alkylation. The method uses amine and alcohol or two kinds of amines as the reaction materials, employs composite metal oxides catalyst at a reaction temperature of 80-180° C. to catalyze the reaction for 6-36 hours, so as to produce the N-substituted amine compound. The reaction condition of the method of the invention is relatively moderate, using a catalyst made of cheap non-noble metals, which is non-caustic and easy to be separated and reused. The reaction does not need any medium and has relatively high conversion rate and selectivity.

Using a simple amino amide ligand, ruthenium-catalyzed one-pot alkylation of primary and secondary amines with simple alcohols was carried out under a wide range of conditions. Using the alcohol as solvent, alkylation was achieved under mild conditions, even as low as room temperature. Reactions occurred with high conversion and selectivity in many cases. Reactions can also be carried out at high temperatures in organic solvent with high selectivity using stoichiometric amounts of the alcohol.

The use of transition-metal nanoparticles/ionic liquid (IL) as a thermoregulated and recyclable catalytic system for hydrogenation has been investigated under mild conditions. The functionalized ionic liquid was composed of poly(ethylene glycol)-functionalized alkylimidazolium as the cation and tris(meta-sulfonatophenyl)phosphine ([P(C6H4-m-SO 3)3]3-) as the anion. Ethyl acetate was chosen as the thermomorphic solvent to avoid the use of toxic organic solvents. Due to a cooperative effect regulated by both the cation and anion of the ionic liquid, the nanocatalysts displayed distinguished temperature-dependent phase behavior and excellent catalytic activity and selectivity, coupled with high stability. In the hydrogenation of α,β-unsaturated aldehydes, the ionic-liquid-stabilized palladium and rhodium nanoparticles exhibited higher selectivity for the hydrogenation of the C=C bonds than commercially available catalysts (Pd/C and Rh/C). We believe that the anion of the ionic liquid, [P(C6H4-m-SO3)3]3-, plays a role in changing the surrounding electronic characteristics of the nanoparticles through its coordination capacity, whereas the poly(ethylene glycol)-functionalized alkylimidazolium cation is responsible for the thermomorphic properties of the nanocatalyst in ethyl acetate. The present catalytic systems can be employed for the hydrogenation of a wide range of substrates bearing different functional groups. The catalysts could be easily separated from the products by thermoregulated phase separation and efficiently recycled ten times without significant changes in their catalytic activity. Copyright

An ecofriendly catalytic route for selective synthesis of N-substituted azacyclopentanes, nitrogen-containing heterocyclic intermediates for many bioactive compounds, was established by carrying out N-heterocyclization (di N-alkylation) of primary amines with 1,4-dichloro butane (as dialkylating agent) using catalytic amount of hydrotalcite as solid base catalyst. The hydrotalcite was found to be efficient solid base catalyst for di Nalkylation of different primary amines (aniline, benzyl amine, cyclohexyl amine and n-butyl amine) giving 82 to 96% conversion (at optimized reaction condition) of 1,4-dichloro butane and > 99% selectivity of respective N-substituted azacyclopentanes within 30 min. under solvent free condition. The reaction parameters significantly influence the conversion of 1,4-dichloro butane to N-substituted azacyclopentanes. The nature of substituent present on amino group affects the reactivity of amine substrates for di N-alkylation reaction with 1,4-dichloro butane. The 1,4-dichloro butane was found to be highly reactive alkylating agent for di Nalkylation of amines as compared to 1,4-dihydroxy butane. The reusability of the catalyst and its chemical stability in the reaction was demonstrated. Copyright

A simple and convenient procedure for the reductive alkylation of primary and secondary amines and N,N-dimethylation of amino acids is described using sodium borohydride as a reducing agent in 2,2,2- trifluoroethanol without use of a catalyst or any other additive. The solvent can be readily recovered from reaction products in excellent purity for direct reuse. Georg Thieme Verlag Stuttgart - New York.

A high-yielding and facile one-pot Leuckart-type reaction for rapid access to a number of 2° and 3° amines is described.

The present invention is directed to a process for isomerizing light paraffins by using a catalyst containing a zeolite selected from the group consisting of CON- and TUN-type zeolites, and at least one Group VIII metal. It has been found that the CON- and TUN-type zeolite catalysts of the present invention selectively convert C6 paraffins into the more favorable higher octane C6 isomer, namely 2,3-dimethylbetane (RON 101.0), over the less favorable C6 isomer, namely octane 2,2-dimethylbutane (RON 91.8).

A fast, efficient, and high-yielding method for the preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of Amberlyst 15 in tetrahydrofuran and under solvent-free conditions at room temperature is described.

A fast, efficient, and high yielding method for the preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of cellulose sulfuric acid in EtOH and under solvent-free conditions at room temperature is described.

A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica chloride as an active, inexpensive, recoverable, and recyclable catalyst is described. The reactions were carried out with equimolar amounts of amine and carbonyl compound using silica chloride-sodium borohydride in THF at room temperature TUeBITAK.

A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described. A variety of aliphatic and aromatic aldehydes, ketones and amines when mixed with NaBH4/silica chloride at room temperature, afforded excellent yield of the corresponding amines.

We report hereby a particularly efficient synthesis of secondary, and tertiary amines respectively, through a direct reductive amination process carried for the first time in a completely aqueous media.

Primary or secondary alcohols will reduce enamines to their corresponding saturated amines when heated in a microwave apparatus at a temperature of 160 °C for a period of one hour.

A regioselective and convenient procedure for preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of sulfuric acid supported on silica gel as an active, inexpensive, and recoverable catalyst under heterogeneous and solvent-free conditions at room temperature is described.

A simple and convenient procedure for reductive amination of aldehydes and ketones using N-methylpyrrolidine zinc borohydride (ZBHNMP) as a reducing agent is described. The reactions are carried out with 1 equiv of amine and 1 equiv of aldehyde or ketone using 1 equiv of ZBHNMP in methanol under neutral conditions at room temperature.

The alkylation of amines by alcohols has been achieved using 0.5 mol percent [Ru(p-cymene)CI2]2 with the bidentate phosphines dppf or DPEphos as the catalyst. Primary amines have been converted into secondary amines, and secondary amines into tertiary amines, including the syntheses of Piribedil, Tripelennamine, and Chlorpheniramine. A/-Heterocyclization reactions of primary amines are reported, as well as alkylation reactions of primary sulfonamides. Secondary alcohols requiremore forcing conditions than primary alcohols but are still effective a lkylating agents in the presence of this catalyst.

A chemoselective, fast, efficient, and high yielding method for the preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica phosphoric acid in THF and under solvent-free conditions at room temperature is described.

Direct reductive amination of aldehydes and ketones were accomplished efficiently using high-capacity, ionene-based, polymer-supported borohydride reagent in isopropyl alcohol at reflux under neutral conditions. The reagent is easily prepared by mixing aqueous solution of 2,4-ionene bromide with an alkaline solution of sodium borohydride at room temperature. The generality of reaction was established using both aliphatic and aromatic aldehydes, ketones, and amines. Copyright Taylor & Francis Group, LLC.

A versatile and highly atom economical catalytic system consisting of [Cp*IrCl2]2/NaHCO3 (Cp*=pentamethylcyclopentadienyl) for the N-alkylation of amines with primary and secondary alcohols as alkylating reagents has been developed. For example, the reaction of equimolar amounts of aniline and benzyl alcohol in the presence of [Cp*IrCl2]2 (1.0 mol % Ir) and NaHCO3 (1.0 mol %) in toluene at 110 °C gives N-benzylaniline in 94% yield. The present catalytic system is applicable to the N-alkylation of both primary and secondary amines, and only harmless water is produced as co-product. A wide variety of secondary and tertiary amines can be synthesized with high atom economy under mild and less-toxic conditions. One-pot sequential N-alkylation leading to tertiary amines bearing three different substituents is also described.

The amination of secondary alcohols to give tertiary amines in the presence of different in situ generated ruthenium catalysts has been investigated in detail. By applying a combination of [Ru3(CO)12] and N-phenyl-2-(dicyclohexylphosphanyl) pyrrole as the catalyst, cyclic amines can be alkylated with different alcohols in high yield, whereas aliphatic amines gave transalkylation side products. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

The asymmetric hydrogenation of N,N-dialkyl and N-alkyl-N-aryl enamines to chiral tertiary amines was studied. All the N,P-ligated iridium complexes investigated were active catalysts for the reaction, but only those with bicycle-supported oxazoline-phosp

The imines were generated in situ from carbonyl compounds and amines, which undergo smooth reduction with sodium borohydride in an ionic liquid/H 2O solvent system. The reaction conditions were very mild and neutral to afford the corresponding highly functionalized amines in excellent yields. Copyright Taylor & Francis Group, LLC.

A one-pot reductive amination of aldehydes and ketones using N-methyl piperidine zinc borohydride as a new and stable reducing agent is described. The reaction has been carried out in methanol at room temperature under neutral conditions. Georg Thieme Verlag Stuttgart.

The synthesis of nitrogen-containing heterocycles from alkyl dihalides (ditosylates) and primary amines and hydrazines via a simple and efficient cyclocondensation in an alkaline aqueous medium that occurs under microwave irradiation is described. This improved greener synthetic methodology provides a simple and straightforward one-pot approach to the synthesis of a variety of heterocycles, such as substituted azetidines, pyrrolidines, piperidines, azepanes, N-substituted 2,3-dihydro-1H-isoindoles, 4,5-dihydropyrazoles, pyrazolidines, and 1,2-dihydrophthalazines.

Benzyltriphenyltriphenylphosphonium borohydride (BTPPB) (1) generated as white solid from benzyltriphenylphosphonium chloride and sodium borohydride is found to be a selective and versatile reducing agent. The reagent in methanol is very useful for reduction of imines, enamines and reductive animation of aldehydes.

Butyltriphenylphosphonium tetraborate (BTPPTB) 1, generated as white solid from butyltriphenylphosphonium bromide and sodium borohydride, is found to be a selective and versatile reducing agent. The reagent in methanol or under solvent-free conditions is very useful for the reduction of imines, enamines and oximes or reductive amination of aldehydes and ketones. Under solvent-free conditions the reactions are faster and the yields of the products are higher.

1-Benzyl-1-azonia-4-azabicyclo[2.2.2]octane tetrahydroborate (BAAOTB) 1 generated as white solid from commercially available DABCO and sodium borohydride is found to be a selective and versatile reducing agent. The reagent in t-butanol is very useful for reduction of imines, enamines, oximes, reductive amination of aldehydes and ketones and reductive methylation of amines.

Azides bearing a suitably disposed alkene, when treated with either mercuric perchlorate or mercuric trifluoromethanesulfonate, produce bicyclic iminium ions. This new version of the Schmidt reaction proceeds by capture of the mercuronium ion intermediate by the azide to produce an aminodiazonium ion, which suffers a 1,2-shift to give an iminium ion (e.g., 10 → 16 → 17 → 18). Reduction of the iminium ion may then be carried out to produce an amine. Compared to earlier work on the protic acid-promoted intramolecular Schmidt reaction of azido-alkenes, the mercury-promoted Schmidt reaction has several advantages. First, the acid-promoted Schmidt reaction of azido-alkenes requires that the intermediate carbocations be tertiary, allylic, benzylic, or propargylic. The mercury-promoted method has no such limitation; thus even 1,2-disubstituted alkenes may be used. Second, the mercury-promoted method is milder, allowing the presence of acid-sensitive functionality. The protic version, typically employing trifluoromethanesulfonic acid, is limited in its functional group tolerance. Third, whereas carbocation rearrangement is often observed prior to cyclization/rearrangement in the acid-promoted Schmidt reaction, the mercury-promoted method avoids this problem. Fourth, the presence of the mercurio group during the rearrangment may alter the regioselectivity of the 1,2-migration. Finally, the mercury-bearing iminium ions that are the result of the Schmidt reaction were found to be sensitive to protodemercuration, precluding their use in other transformations.

Various 5- and 6-membered tertiary lactams were reduced to the corresponding cyclic tertiary amines using 2.2 to 2.5 equivalents of 9- borabicyclo[3.3.1]nonane (9-BBN). This method is highly chemoselective and it is easy to reduce a lactam in the presence of an ester.