CAN mediated decarboxylative hydroxylation/alkoxylation of N-aryl-γ-lactam-carboxylic acids at room temperature: an easy access to N-aryl-α-hydroxy/alkoxy-γ-lactams

An efficient and mild protocol for one-pot decarboxylative hydroxylation/alkoxylation of 1,3-diaryl-5-oxo-pyrrolidine-2-carboxylic acids to trans-5-hydroxy-1,4-diarylpyrrolidin-2-ones and 5-alkoxy-1,4-diaryl-1,5-dihydropyrrol-2-ones at room temperature using CAN in organo-aqueous solvent has been developed.     

Copper catalyzed borylative cyclization of 3-arylallyl carbamoyl chloride with B2pin2: stereoselective synthesis of cis-2-aryl-3-boryl-γ-lactams

Borylative cyclization of E-3-arylallyl carbamoyl chlorides is achieved through copper catalyzed intramolecular carboboration with B₂pin₂. 2-Aryl-3-boryl-γ-lactams are formed with exclusive cis-diastereoselectivity. CuBr-Dppp combination gives the best outcomes. The substrate scope is profiled.     

The NHCs-mediated cross-coupling of aromatic aldehydes with benzyl halides: synthesis of α-aryl ketones

A new NHCs-mediated synthetic method was found to produce α-aryl ketones in 22-63% yields in one-pot process from the corresponding aromatic aldehydes and benzyl halides. This method is the first example of the NHCs-mediated intermolecular nucleophilic acylation of aromatic aldehydes with benzyl halides.     

N-Chlorosuccinimide as a versatile reagent for the sulfenylation of ketones: a facile synthesis of α-ketothioethers

The sulfenylation of ketones having α-hydrogens has been achieved using N-chlorosuccinimide (NCS) under mild reaction conditions to produce α-ketothioethers in excellent yields with high selectivity. The use of NCS makes this method quite simple, convenient and practical.     

Stereoselective tribromomethylation of N-(tert-butanesulfinyl)imines with bromoform: practical synthesis of α-tribromomethyl amines

The unprecedented nucleophilic tribromomethylation of N-(tert-butanesulfinyl)imines with bromoform has been shown to be a highly stereoselective and practical method for the synthesis of enantiomerically pure α-tribromomethyl amines. THF has proven to be the best solvent in this addition reaction. By changing the reaction solvent from THF to DMF, 2,2-dibromoaziridines can also be synthesized directly from bromoform and N-(tert-butanesulfinyl)imines under similar reaction conditions.     

Heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyzed direct synthesis of diamines from N-alkylation of amines with diols through a borrowing hydrogen strategy

Direct synthesis of diamines has been efficiently realized from the N-alkylation of amines with diols by means of heterogeneous bimetallic Pt-Sn/γ-Al₂O₃ catalyst (0.5 wt % Pt, molar ratio Pt:Sn = 1:3) through a ‘Borrowing Hydrogen’ strategy under ligand-free conditions. The present methodology provides an environmentally benign route to diamines.     

Pd(II)-catalyzed annulation of N-benzyl-N-aroylmethyl-2-alkynamides with arylboronic acids: an efficient synthesis of highly substituted α-alkylidene-β-hydroxy-γ-lactams

A simple palladium(II)-catalyzed intramolecular addition of vinylpalladium species to ketones initiated by the carbopalladation of alkynamides under mild conditions without a Pd(II)/Pd(0) redox system was developed. This cascade reaction provides a new approach for the synthesis of highly substituted α-alkylidene-β-hydroxy-γ-lactams.     

Direct palladium/copper oxidative cross-coupling of α-methylstyrene with acrylates

Fully palladium/copper catalytic oxidative cross-coupling of acrylates with α-methylstyrene was performed in a DMSO/AcOH (1:1) mixture at 60 °C in the air. This improves previous procedures which employed stoichiometric amounts of copper and oxygen. Thus various acrylates were effectively coupled to α-methylstyrene giving the expected compounds in moderate to good yields (44%–65%) as a mixture of E and Z isomers.     

Photocatalytic aerobic cross-coupling reaction of N-substituted anilines with N-aryl glycine esters: Synthesis of α-aryl α-amino esters

A novel photocatalytic cross dehydrogenative coupling reaction of N-aryl glycine esters with N-substituted anilines has been developed. The reaction proceeds effectively using methylene blue as a photocatalyst under visible light irradiation without any metal, chemical oxidant or additive. A variety of α-aryl α-amino derivatives were prepared in moderate to excellent yields with a high para-regioselectivity.     

SmI2-mediated cross-coupling of nitrones with β-silyl acrylates: synthesis of (+)-australine

The SmI(2)-mediated cross-coupling of nitrones with β-silyl-α,β-unsaturated esters, followed by zinc reduction, allows an efficient and highly diastereoselective preparation of β-silyl lactams, which are precursors of β-hydroxy lactams through Tamao-Fleming oxidation. By applying the method to a cyclic, carbohydrate-derived nitrone, a new synthesis of (+)-australine has been realized in only 11 steps and in 21% overall yield from L-xylose.     

Regiospecific synthesis of α-methylene-β-lactams by a homogeneous palladium catalyzed ring expansion-carbonylation reaction

Tetrakis(triphenylphosphine)palladium(O) [or palladium acetate and added triphenylphosphine] catalyzes the carbonylation of methyleneaziridines to _α-methylene-_β-lactams at room temperature and one atmosphere.     

One-pot synthesis of chiral α-methylene-γ-lactams with excellent diastereoselectivities and enantioselectivities

An efficient one-pot asymmetric synthesis of highly substituted γ-lactams containing α-methylene groups has been successfully developed. A wide range of γ-lactams could be obtained in high yields with excellent diastereomeric ratios of up to 99:1 in favor of trans isomers. In particular, excellent enantioselectivities of the two newly formed stereogenic centers with up to 99% ee were observed.     

Regioselective ring opening of β-phenylglycidate and aziridine-2-carboxylates with N-alkylhydroxylamines: synthesis of isoxazolidinones

A simple and efficient method for the synthesis of 4-hydroxy or 4-alkylamino isoxazolidin-3-ones and 4-hydroxy isoxazolidin-5-ones is described. The synthesis involved the ring opening of ethyl β-arylglycidates or ethyl N-alkylaziridine-2-carboxylates by free N-alkylhydroxylamines or hydroxylamine anions, followed by cyclization to give the title isoxazolidinones in moderate to good yields.     

N-Carbamate α-aminoalkyl-p-tolylsulfones—convenient substrates in the nitro-Mannich synthesis of secondary N-carbamate protected syn-2-amino-1-nitroalkanephosphonates

An efficient one-pot synthesis of secondary N-carbamate protected syn-β-amino-α-nitroalkanephosphonates using diethyl nitromethanephosphonate and N-Boc or N-Cbz imines, generated in situ from stable N-Boc or N-Cbz α-aminoalkyl-p-tolylsulfones has been developed under PTC conditions. A model enantioselective version of this reaction is also described. Enantioselectivity up to 67% ee is achieved using a chiral thiourea catalyst derived from a cinchona alkaloid. Completely stereoselective conversion of the title compounds into partially N-carbamate protected syn-1,2-diaminoalkanephosphonates has also been elaborated.     

SmI2-mediated coupling of nitrones and tert-butanesulfinyl imines with allenoates: synthesis of β-methylenyl-γ-lactams and tetramic acids

Nitrones and tert-butanesulfinyl imines undergo conjugate addition to alkyl allenoates under SmI(2)-mediated reductive coupling conditions to produce novel β-methylenyl-substituted γ-amino esters. The latter were readily transformed into the corresponding β-methylenyl-γ-lactams by simple zinc reduction (N-hydroxy amines) or by acid hydrolysis (sulfinamides). The diastereoselective preparation of various β-methylenyl-γ-lactams offers a route to tetramic acids, the key structural features of an important class of bioactive natural products.     

Efficient synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines catalyzed by CuFe2O4 nanoparticles

A simple and efficient method has been developed for the synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines in the presence of CuFe₂O₄ nanoparticles as a heterogeneous recyclable catalyst at room temperature in high yields.     

Stereocontrolled synthesis of α-amino-α'-alkoxy ketones by a copper-catalyzed cross-coupling of peptidic thiol esters and α-alkoxyalkylstannanes

A stereocontrolled synthesis of α-amino-α'-alkoxy ketones is described. This pH-neutral copper(I) thiophene-2-carboxylate (CuTC)-catalyzed cross-coupling of amino acid thiol esters and chiral nonracemic α-alkoxyalkylstannanes gives α-amino-α'-alkoxy ketones in good to excellent yields with complete retention of configuration at the α-amino- and α-alkoxy-substituted stereocenters.     

A highly α-regioselective In(OTf)3-catalyzed N-nucleophilic substitution of cyclic Baylis-Hillman adducts with aromatic amines

The highly α-regioselective N-nucleophilic substitution of B-H adducts bearing five (1a-f) or six-membered ring (5a-e) moieties with aromatic amines (2a-e) was developed under the catalysis of In(OTf)₃ (10 mol%). During the reaction the allylic rearrangement from γ-product to α-product occurred, resulting in thermodynamically stable α-product predominately.     

Chemoselective cross-coupling of terminal propargylamines with (het)aroyl chlorides: synthesis of β-aminoacetylenic ketones bearing aromatic and heteroaromatic substituents

Russian Chemical Bulletin - Terminal secondary 4-chlorophenyl propargylamines, synthesized by addition of acetylene to N-(4-chlorophenyl)ketimines (ButOK, DMSO, 20–25 °C) in 76–93%...     

Aqueous media carboxylative cyclization of propargylic amines with CO2 catalyzed by amphiphilic dendritic N-heterocyclic carbene–gold(I) complexes

We prepared amphiphilic dendritic N-heterocyclic carbene (NHC)–gold(I) complexes having poly(ethylene glycol) units at the peripheral layer. By employing 1 mol % of the dendritic NHC–gold(I) catalyst, the aqueous media carboxylative cyclization of propargylic amines proceeded smoothly to provide the corresponding 2-oxazolidinone under atmospheric pressure of CO₂ at room temperature.