17692-84-1

B2Pin2-assisted copper-catalyzed transfer hydrogenation of aromatic sulfonylimines has been achieved, delivering a variety of aryl/heteroaryl sulfonamides in good to excellent yields under mild reaction conditions and with methanol a

Herein, we report a Kumada cross-coupling reaction of benzylic sulfonamides. The scope of the transformation includes acyclic and cyclic sulfonamide precursors that cleanly produce highly substituted acyclic fragments. Preliminary data are consistent with a stereospecific mechanism that allows for a diastereoselective reaction.

We have developed a palladium-catalyzed regioselective and enantiospecific ring-opening Suzuki–Miyaura arylative cross-coupling of N-tosyl-2-arylazetidines to give enantioenriched 3,3-diarylpropylamines. This reaction represents an example of transition-metal-catalyzed ring-opening cross-coupling using azetidines as a non-classical alkyl electrophile. Density functional theory rationalized the mechanism of the full catalytic cycle, which consists of the selectivity-determining ring opening of the azetidine, reaction with water, rate-determining transmetalation, and reductive elimination. Transition states of the selectivity-determining ring-opening step were systematically determined by the multi-component artificial force induced reaction (MC-AFIR) method to explain the regioselectivity of the reaction. (Figure presented.).

A nickel-catalyzed reductive coupling of alkynes and imines using readily available isopropanol as the reducing agent was developed. The use of a sterically bulky and electron-rich carbene ligand (AnIPr) significantly promotes the reaction, providing various multi-substituted allylic amines in 23-89% yield and the corresponding chiral ligand (AnIPr-3) can afford the products in 51-95% ee.

A functional group exchange reaction between allylamines and alkenes via nickel-catalyzed C - C bond cleavage and formation was developed. This reaction provides a novel protocol, which does not require the use of unstable imine substrates, for the synthesis of allylamines, which are widely used in the production of fine chemicals, pharmaceuticals, and agrochemicals.

A practical catalytic method to synthesize β,β- and γ,γ-substituted amines by opening aziridines and azetidines, respectively, using alkenyl, alkynyl, or aryl/heteroaryl trifluoroborate salts is described. This reaction features simple open-flask reaction conditions, the use of transition-metal-free catalysis, complete regioselectivity, and high diastereoselectivity. Preliminary mechanistic studies suggest that carbocation formation is disfavored. Stereoretentive addition is favored with Br?nsted acid present, while stereoinversion is favored in its absence, indicating divergent mechanisms.

Proazaphosphatranes -Verkade's superbases- proved to be efficient organocatalysts for the Strecker reaction between protected imines and trimethylsilyl cyanide (TMSCN). Excellent to quantitative yields were reached and, compared to other systems, only low

A straightforward method for the visible-light-mediated decarboxylative benzylation of imines is reported. The key feature of this method is the use of simple primary, secondary, and tertiary arylacetic acids as precursors of benzyl radicals, enabling the facile benzylation of a variety of imines under mild conditions. A variety of structurally diverse β-arylethylamines (37 examples) was accessed using this method.

Benzylic N-substituted stereocenters constitute a frequent structural motif in drugs. Their highly enantioselective generation is hence of technical importance. An attractive strategy is the arylation of imines with organoboron reagents. Chiral Rh complexes have reached a high level of productivity for this reaction type. In this article we describe that an electron rich PdIIcatalyst also performs well in the arylation of aldimines, comparable to the best Rh catalysts. The ferrocenyl palladacycle-acetate catalyst allows for a broad substrate scope and very high enantioselectivities. Commonly observed side reactions like aryl–aryl homocouplings and imine hydrolysis could be blocked. Mechanistic studies implicate that a) the acetate ligand is crucial for transmetallation, b) the active catalyst is most likely a palladacycle-OAc monomer, c) the rate limiting step is probably the product release. By added KOAc the arylation could also be applied to ketimines.

A palladium-catalyzed intramolecular amination of alkenes with retention of olefin functionalization was achieved under mild reaction conditions. In the presence of palladium catalyst, the tosyl-protected amine can directly couple with a double bond to provide versatile dihydropyrrole derivatives in moderate to excellent yields.

Asymmetric arylation of aldimines catalyzed by heterogeneous chiral rhodium nanoparticles has been developed. The reaction proceeded in aqueous media without significant decomposition of the imines by hydrolysis to afford chiral (diarylmethyl)amines in high yields with outstanding enantioselectivities. This catalyst system exhibited the highest turnover number (700) in heterogeneous catalysts reported to date for these reactions. The reusability of the catalyst was also demonstrated.

A green method for epoxidation of imines using an environmentally benign oxidant system, H2O2/dimethyl carbonate, was developed. N-Alkyloxaziridines were prepared in high yields from N-alkylamines and (hetero)aromatic aldehydes in one-pot fashion, whereas N-sulfonyloxaziridines have been prepared by using the same oxidant system and 5 mol% of Zn(OAc)2·2H2O as catalyst.

Catalysis using a bis(dialkylamino)cyclopropenylidene (BAC) has been developed, which relies on a formal umpolung activation of Michael acceptor pro-nucleophiles. Various aza-Morita-Baylis-Hillman reactions between aromatic, heteroaromatic, or aliphatic imines and acyclic or cyclic α,β-unsaturated ketones and carboxylic acid derivatives have been catalyzed by a BAC under mild conditions. Functionalities such as unprotected amino and hydroxy groups have been tolerated. The catalyst loading was decreased to 1 mol% without loss of activity. The BAC catalyst was shown to be substantially more active than a cyclic (alkyl)(amino) carbene (CAAC), N-heterocyclic carbenes (NHCs), and P- or N-centered Lewis bases.

-

A carbon activation method that operates through N-heterocyclic carbene/Bronsted acid cooperative catalysis for highly enantioselective synthesis of γlactams is reported. The protocol allows the challenging remote carbon control of regioselectivity and en

Enantiomerically pure benzylic amines are important for the development of new drugs. A readily accessible planar-chiral ferrocene-derived palladacycle is shown to be a highly efficient catalyst for the formation of N-substituted benzylic stereocenters; t

(2,2,2-Trifluoroethyl)diphenylsulfonium triflate was found to be an efficient ylide reagent for the Johnson-Corey-Chaykovsky reaction to afford trifluoromethyl epoxides, cyclopropanes and aziridines. Interestingly, excellent but different diastereoselectivity was observed for these transformations. Both trifluoromethyl epoxides and cyclopropanes were obtained with trans-selectivity, whereas aziridines were obtained with cis-selectivity.

An efficient FeCl3-catalyzed three-component reaction between aldehydes, sulfonamides and allylsilanes has been achieved, which provides a convenient, atom-economic and green way to construct homoallylamine derivatives. In addition, this reaction exhibits excellent syn stereoselectivity with γ-substituted allylsilanes. A practical three-component cascade process to homoallylamine derivatives is reported, which uses cheap and environmentally benign FeCl3 as catalyst and shows excellent syn stereoselectivity with γ-substituted allylsilanes.

An isothiourea-catalyzed Michael addition-lactamization followed by the sulfide oxidation-elimination/N- to O-sulfonyl transfer sequence for the formation of 2,3,5- and 2,3-substituted pyridine 6-tosylates from (phenylthio)acetic acids and α,β-unsaturated

Enantioselective Friedel-Crafts reactions between phenols and N-tosylaldimines were developed using a bifunctional catalyst readily prepared from l-leucine. The chiral benzylic amine products were obtained in high yields (up to 96% yield) and good to high enantiomeric excesses (up to 95% ee).

For the first time, we report the application of [RuCl2(η 6-p-cymene)]2 in the arylation of N-activated aldimines with boronic acids and its derivatives to afford chiral amines, which are important intermediates in the syntheses of key bioactive compounds. The behavior of the chiral ligands, the imine substrates, and the organoboron reagents were studied. Very good enantioselectivities were obtained. A new method is presented for the synthesis of chiral substituted amines by employing Ru catalysts along with known chiral phosphane ligands and a new NHC-type chiral ligand. Organoboron reagents were applied as the aryl transfer agents. High enantioselectivities were achieved with this new method, and some mechanistic insights are provided.

A new approach to additions of silicon nucleophiles to imines was developed. The method is based on the phase-transfer of phenoxides by ammonium catalysts, overcoming the inability of amide adducts in promoting the reactions.

Indolines bearing different N-protecting groups (N-Tbf and N-Boc) were deprotonated regioselectively at C-2 (sp3 hybridized ortho-H) and C-7 (sp2 hybridized para-H) of the indoline ring, respectively. The generated organolithium intermediates reacted with aldimines to give the desired products in good yields with excellent anti-diastereoselectivities (>99:1). The produced N-Ts-(1-Tbf-indolin-2-yl)methanamine was facilely transformed to a fused heterocyclic compound.

We report three transformations: 1) direct transformation from biarylmethanols into biarylmethylamines; 2) direct transformation from one biarylmethanol into another biarylmethanol; 3) direct transformation from allylic alcohols into allylic amines. These transformations are based on pyridyl-directed Rh-catalyzed C-C bond cleavage of secondary alcohols and subsequent addition to C=X (X=N or O) double bonds. The reaction conditions are simple and no additive is required. The driving force of C-C bond cleavage is the formation of the stable rhodacycle intermediate. Other directing groups, such as the pyrazolyl group, can also be used although it is not as efficient as the pyridyl group. We carried out in-depth investigations for transformation 1 and found that: 1) the substrate scope was broad and electron-rich alcohols and electron-deficient imines are more efficient; 2) as the leaving group, aldehyde had no significant impact on either the C-C bond cleavage or the whole transformation; 3) mechanistic studies (intermediate isolation, in situ NMR spectroscopic studies, competing reactions, isotopic labeling experiments) implied that: i) The C-C cleavage was very efficient under these conditions; ii) there is an equilibrium between the rhodacycle intermediate and the protonated byproduct phenylpyridine; iii) the addition step of the rhodacycle intermediate to imines was slower than the C-C cleavage and the equilibrium between the rhodacycle and phenylpyridine; iv) the whole transformation was a combination of two sequences of C-C cleavage/nucleophilic addition and C-C cleavage/protonation/C-H activation/nucleophilic addition, with the latter being perhaps the main pathway. We also demonstrated the first example of cleavage of an C(alkenyl)-C(benzyl) bond. These transformations showed the exchange (or substitution) of the alcohol group with either an amine or another alcohol group. Like the "group transplant", this method offers a new concept that can be used to directly synthesize the desired products from other chemicals through reorganization of carbon skeletons.

An imino-Nazarov cyclization using α-aryl-substituted allenamides is described. This gold(I)-catalyzed cascade is efficient and regioselective in constructing a diverse array of synthetically useful aromatic-ring fused cyclopentenamides. The success in this transformation represents a solution to the challenge in establishing an imino-Nazarov cyclization process.

Ruthenium(II)-catalyzed redox-neutral annulative coupling of N-sulfonyl imines with alkynes has been achieved for the synthesis of indenamines, where a sulfonamide cocatalyst is necessary.

A new chiral zinc-amide 2s' was found to be an effective catalyst for the asymmetric addition of diethylzinc to aldehydes 3 through a screening method for asymmetric catalysts, in which two catalytic asymmetric reactions are connected. The chiral zinc cat

The asymmetric Friedel-Crafts amidoalkylation of indoles with aryl aldimines could be efficiently catalyzed by Trost's bis-ProPhenol dinuclear zinc complexes to attain 3-indolyl methanamine derivatives in good to excellent yields (85-98%) with moderate to high enantiomeric ratios (from 70:30 up to 95:5 er). Remarkably, this approach provides efficient access to enantiomerically enriched 3-indolyl methanamines, which avoids the formation of the undesirable bis- and tris(indolyl)methanes (BIMs and TIMs) byproduct.

A metal-free method for performing the Strecker reaction of N-tosylaldimines with ethyl cyanoformate in dimethylsulf-oxide (DMSO) has been developed. Various types of N-tosyl-aldimines undergo the cyanation to provide the N-protected -amino nitriles. This

A highly efficient and selective Friedel-Crafts amidoalkylation reaction of indoles with N-Ts aryl aldimines has been developed utilizing dimethyl hydrogen phosphite or diphenyl hydrogen phosphate as the organocatalysts, providing a facile and cost-effect

(Chemical Equation Presented) The cycloaddition of o-(silylmethyl)benzylic carbonates with imines proceeded in the presence of the Pd(η3- C3H5)Cp-DPPPent catalyst, affording the tetrahydroisoquinolines in good to high yiel

N-Heterocyclic carbenes promote the formal [2+2] cycloaddition of ketenes with N-tosyl imines to give the corresponding β-lactams in good to excellent isolated yields; chiral NHCs give β-lactams in high e.e. after crystallisation.

Organocatalytic direct anti-selective Mannich reactions of O-TBS-hydroxyacetone with various N-tosylimines derived from aromatic aldehydes in the presence of L-threonine-derived catalyst afforded 1,2-amino alcohols in good yields and with enantioselectivi

-

(Chemical Equation Presented) A simple procedure to obtain N-sulfonyl imines involving the condensation of carbonyl compounds with p-tolyl or tert-butyl sulfinamides followed by oxidation with m-CPBA of the resulting N-sulfinylimines is reported. The meth

Synthesis of N-tosylimines of arylaldehydes was carried out by the reaction of arylaldehydes and p-toluenesulfonamide in methylene chloride in the presence of trifluoroacetic anhydride as a dehydrating agent.

Palladium-catalyzed intermolecular reaction of imines (1) with vinylic oxiranes (2) gives the regioselective [3+2] cycloaddition products, 1,3- oxazolidine derivatives (3), in good to excellent yields. The present reaction permits the use of uncoventional

The reaction of phosphinic amides or sulphonamides with an aromatic aldehyde in the presence of titanium tetrachloride and triethylamine provides a simple, one-step preparation of N-phosphinoylimines (5a-e) and N-sulphonylimines (7a-g). The extension of this reaction to ketones failed to give the desired imines, the aldol condensation products were obtained instead. The reaction of (+)-camphor with phosphinic amides or sulphonamides in refluxing toluene in the presence of titanium tetrachloride and triethylamine affords the (-)-camphorphosphinoyl- and (-)-camphorsulphonylimines in moderate yield.

Reaction of phosphinamides and sulphonamides with aromatic aldehydes at 0 deg C in the presence of titanium tetrachloride and triethylamine provides a simple one-step preparation of N-phosphinoyl and N-sulphonyl imines.