Asymmetric synthesis of protected 1,2-amino alcohols using tert-butanesulfinyl aldimines and ketimines.

tert-Butanesulfinyl aldimines and ketimines bearing an alpha-benzyloxy or alpha-silyloxy substituent serve as precursors in the synthesis of protected 1,2-amino alcohols in high yields and diastereoselectivities. General protocols are described for the addition of unbranched alkyl, branched alkyl, and aryl organometallic reagents to N-sulfinyl aldimines 1 and 2 and ketimines 5 and 6. Furthermore, the selective N- or O-deprotection of sulfinamide products 3, 4, 7, and 8 is described, enabling further synthetic transformations of the reaction products.     

Ruthenium-catalyzed coupling of aldimines with arylboronates: new synthetic method for aromatic ketones

Using the chelation strategy, the reaction of aldimines bearing the 3-picolin-2-yl group with various arylboronates in the presence of a ruthenium catalyst furnished the corresponding ketimines in high yields for a short reaction time; the resulting ketimines were readily converted to ketones by hydrolysis.     

Reduction and reductive coupling of imines by Sm(II)-based reagents

The reductive coupling of aldimines and ketimines by a series of Sm(II)-based reagents (SmI₂, SmI₂–HMPA, SmBr₂, Sm{N[Si(CH₃)₃]₂}₂, and SmI₂/triethylamine/water) were examined. In general, aldimines and ketimines were efficiently reduced or coupled using reductants that are more powerful than SmI₂, and the use of Sm{N[Si(CH₃)₃]₂}₂ led to higher diastereoselectivities in reductive coupling reactions. Surprisingly, only the combination of SmI₂/triethylamine/water was capable of reducing and coupling para-substituted benzaldimines and coupling ketimines.     

Asymmetric aza-Henry reactions from N-p-tolylsulfinylimines

[reaction: see text] N-Sulfinylimines derived from aromatic or aliphatic aldehydes and ketones react with nitromethane and NaOH in a highly diastereoselective manner under mild conditions. In the presence of TBAF, the reaction rates are strongly increased and the stereoselectivity is inverted. This method provides enantiomerically pure beta-nitroamines derived from enolizable aldimines and ketimines, which so far are hardly accessible by aza-Henry reactions.     

A Convenient Synthesis of 4-Amino-3-trimethylsilylalk-1-enes

Pinacol-E-1-trimethylsilyl-1-propene-3-boronate regiospecifically reacts with aldimines and ketimines to lead to 4-amino-3-trimethylsilylalk-1-enes with good yields.     

Metal-free catalytic reduction of aldehydes,ketones,aldimines,and ketimines

<正>The metal-free combination of catalytic amounts of PPh_3,B(C_6F_5)_3,and PhSiH_3 can efficiently hydrosilylate aldehydes, ketones,aldimines and ketimines to afford the corresponding reduction products in good yields.     

Microwave-assisted solvent-free synthesis of enantiomerically pure N-(tert-butylsulfinyl)imines

A simple, environmentally friendly, and very efficient procedure for the synthesis of optically pure N-(tert-butylsulfinyl)imines has been developed with microwave-promoted condensation of aldehydes and ketones using (R)-2-methylpropane-2-sulfinamide in the presence of Ti(OEt)(4), under solvent-free conditions. This procedure allows for the preparation of a variety of sulfinyl aldimines with excellent yields and purities in only 10 min, making any further purification of the imines unnecessary. Several sulfinyl ketimines have also been prepared in good yields by extension of the reaction times to 1 h. This methodology has proved to be equally efficient for the synthesis of aromatic, heteroaromatic, and aliphatic N-(tert-butylsulfinyl)imines. Conventional heating has also been shown to be useful to promote these reactions, especially for the synthesis of aldimines.     

An efficient method for the phosphonation of C=X compounds

Reaction of trialkyl phosphites with C=X electrophiles (aldehydes, ketones, ketophosphonates, aldimines, ketimines, isocyanates, isothiocyanates, and activated olefins) in the presence of amines and anilines hydrohalides was studied. We found that pyridine hydrohalides effectively activate the reaction of tralkyl phosphites with various C=X electrophiles: aldehydes, ketones, ketophosphonates, aldimines, ketimines, isocyanates, isothiocyanates, and activated olefins. Particularly high activity showed pyridine hydroiodide. This reaction is a convenient method of synthesis of hydroxyphosphonates, aminophosphonates, carbamoylphosphonates, carbamoylthiophosphonates, and methylenebisphosphonates.     

Stereoselective aza-Darzens reactions of tert-butanesulfinimines: convenient access to chiral aziridines

Stereoselective synthesis of 2,3-di- and 2,2',3-tri-substituted aziridines in good yields and excellent diastereoselectivities are achieved through aza-Darzens reactions of a range of tert-butanesulfinyl aldimines and ketimines with ethyl bromoacetate.     

Synthesis of New Schiff Bases and Polycyclic Fused Thiopyranothiazoles Containing 4,6‐Dichloro‐1,3,5‐Triazine Moiety

New aromatic aldimines, isatine substituted ketimines based on (4,6‐dichloro‐1,3,5‐triazin‐2‐yl)‐hydrazine scaffold and polycyclic fused thiopyranothiazoles formed using hetero‐Diels‐Alder reactions starting from 4‐thioxo‐2‐thiazolidinones and 5‐norbornene‐2,3‐dicarboxylic acid triazino‐derivatives synthetic approach is described. The application of condensation and cyclocondensation reactions of N‐nucleophiles and carbonyl agents for synthesis a number of biologically active triazine derivatives is reported. Screening of anticancer activity in vitro yielded the most active compounds 3a , 8b , and 8f for different cell lines.     

Zinc-mediated highly α-regioselective prenylation of imines with prenyl bromide

A highly α-regioselective prenylation of imines has been successfully developed. The efficiency of this approach is confirmed by a wide range of imines including N- and C-aryl aldimines, N-alkyl aldimines, C-alkyl aldimines, and N- and C-aryl ketimines. The approach uses prenyl bromide as the prenyl source and inexpensive and convenient zinc as the mediator as well as environmentally benign 1,3-dimethyl-2-imidazolidinone (DMI) as the solvent.     

Enantioselective catalytic ring expansion of methylenecyclopropane carboxamides promoted by a chiral magnesium Lewis acid

A catalytic enantioselective ring expansion of monoactivated methylenecyclopropanes (MCP) in the presence of N-tosyl aldimines was developed using a chiral bis(oxazoline) ligand-MgI2 complex. After evaluation of ligands and optimization of the reaction conditions, the reaction has been applied to a variety of aromatic and heteroaromatic aldimines providing the corresponding trans-C2,C3-disubstituted methylenepyrrolidines in generally good yields (greater than 52%) and up to 86% ee. [reaction: see text].     

Green,Catalyst-Free Protocol for the Efficient Synthesis of N-Sulfonyl Aldimines and Ketimines in Ionic Liquid [Bmim]Br

Sulfonamides are efficiently condensed with aldehydes as well as ketones in the absence of catalyst in 1-butyl-3-methylimidazolium bromide ([bmim]Br) under microwave irradiation to afford N-sulfonyl aldimines and ketimines in good to excellent yields in short reaction times.     

Reaction du gem-chloro(methyl)allyllithium sur les aldimines et les cetimines: nouvelle methode de synthese d'aziridines α-ethyleniques N-substituees

N-substituted α-ethylenic aziridines are easily prepared by treating gem-chloro-(methyl)allyllithium with aldimines and ketimines.     

碲氢化钠还原亚胺的方法

本文报道一种还原亚胺的新方法。取代的芳基和脂肪基亚胺可以在较温和的条件下被碲氢化钠顺利地还原为相应的仲胺。     

The Role of Sulphonamides and N-Sulphonyl Ketimines/Aldimines as Directing Groups in the Field of C−H Activation

Sulphonamides and N-sulphonyl ketimines/aldimines have turned out to be versatile motifs in the field of synthetic and medicinal chemistry. The field of C−H activation/functionalization flourished remarkably due to their synthetic applicability and directing group plays a remarkable role to achieve regioselectivity in these reactions. The current review summarizes recent tactics by utilizing sulphonamides and N-sulphonyl ketimines/aldimines as directing groups for C−H activation or functionalization. As a directing group, they also facilitate site selectivity and late-stage functionalization of drug molecules in order to construct complex scaffolds of therapeutic importance by C−H activation.     

Zinc-Catalyzed Reduction of Imines by Triethylsilane

Low-cost zinc is employed as a catalyst along with triethylsilane (TES) in a simple, straightforward, chemoselective reduction of various aldimines and ketimines to the corresponding secondary amines at room temperature and pressure.     

Stereoselective monofluoromethylation of N-tert-butylsulfinyl ketimines using pregenerated fluoro(phenylsulfonyl)methyl anion

Pregeneration of fluoro(phenylsulfonyl)methyl anion (PhSO(2)CHF(-)) paves the way for the efficient and highly stereoselective monofluoromethylation of (R)-N-tert-butylsulfinyl ketimines. The stereocontrol mode of the present diastereoselective monofluoromethylation of ketimines is different from the previously known nucleophilic fluoroalkylation of (R)-N-tert-butylsulfinyl aldimines, which suggests that a cyclic six-membered transition state (rather than a nonchelation controlled one) is involved in the current ketimine reaction.     

Asymmetric conjugate addition of copper reagents to alpha,beta-unsaturated tert-butanesulfinyl imines

[reaction: see text] Addition of organocuprates to N-sulfinyl alpha,beta-unsaturated imines proceeds in good yields and with good diastereoselectivities. alpha,beta-Unsaturated sulfinyl ketimines and aldimines have both been shown to be suitable substrates for this reaction.     

Asymmetric synthesis of beta-amino acid derivatives incorporating a broad range of substitution patterns by enolate additions to tert-butanesulfinyl imines

Addition of Ti(Oi-Pr)(3) ester enolates to tert-butanesulfinyl aldimines and ketimines provided beta-substituted, alpha,beta- and beta,beta-disubstituted, alpha,beta,beta- and alpha,alpha,beta-trisubstituted, and alpha,alpha,beta,beta-tetrasubstituted beta-amino acid derivatives in high yields and with high diastereoselectivites. The N-sulfinyl-beta-amino ester products were further employed as versatile intermediates for both standard solution-phase and solid-phase synthetic transformations, including the synthesis of beta-peptide foldamers.