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Diethylzinc was treated with 1 or 2 equiv. of AlkMgCl or PhMgBr (preferably) or with 1 equiv. of nBuLi (less efficiently) for forming species – plausibly zincates – which were sulfinylated by diaryl sulfoxides to give racemic alkyl aryl sulfoxides in yields reaching 100 %. Dialkylzinc reagents were also activated by treatments with 1 or 2 equiv. of an enantiomerically pure alkylmagnesium β-aminoalkoxide. This worked best when the alkoxide stemmed from a dialkylmagnesium reagent and an equimolar amount of N-methyl-(–)-ephedrine. This second activation mode allowed sulfinylations of what was originally the dialkylzinc reagent with diaryl sulfoxides. This generated alkyl aryl sulfoxides with enantiomeric ratios up to 93:7 in up to 100 % yield.

The iridium-f-amphox-catalyzed asymmetric hydrogenation of racemic α-amino β-unfunctionalized ketones proceeds via a DKR (dynamic kinetic resolution) process for the construction of various chiral N,N-disubstituted α-amino β-unfunctionalized alcohols in quantitative yields with excellent enantioselectivities and diastereoselectivities (all products >99% ee and >99:1 dr, TON up to 100 000). Importantly, this catalytic asymmetric hydrogenation with a DKR process provided a highly efficient and powerful synthetic strategy for the preparation of key chiral intermediates of the preclinical antitumor agent (S,S)-R116010.

An in situ-generated complex from [RuCpCl2]2 and dpePhos ligand is reported as an efficient catalyst in the presence of 5 mol % of LiOtBu for the N-methylation of amines using methanol as the methylating agent at moderate conditions, following hydrogen borrowing strategy. This simple catalyst system provides selective N-monomethylation of substituted primary anilines and sulfonamides as well as N,N dimethylation of primary aliphatic amines in excellent yields at 40-100 °C with good tolerance to reducible functional groups. The catalytic intermediate CpRu(dpePhos)H was isolated and was shown to be active for methylation in the absence of base.

Putting CO2 to work: Carbon dioxide is shown to be a general and selective methylating reagent for secondary and primary, aromatic and aliphatic amines under reductive conditions. A variety of tertiary amines are obtained from CO2 and commercially available silanes in high yields with good tolerance to nitrile, olefin, ether, ester, and hydroxy groups. Copyright

The ephedrine-based diselenide appears as a new promiscuous catalyst, able to generate optically active alcohols by addition of organozinc to aldehydes (up to 97% ee), and shows powerful GPx like activity, reducing H2O 2 to water in only 16.33 min (eleven times faster than PhSeSePh).

Ephedrine-derived bifunctional thioureas have been synthesized and applied as organocatalysts in Michael additions of 1,3-dicarbonyl compounds to nitroalkenes. Georg Thieme Verlag Stuttgart.

An efficient procedure for the synthesis of functionalized chiral ammonium, imidazolium, and pyridinium-based ionic liquids derived from (IR, 2S)-ephedrine using solvent-free microwave activation has been described. Good yields were obtained in very short reaction time. These chiral ionic liquids were used as chiral reaction media for the asymmetric Michael addition, giving good yields and moderate enantioselectivities.

One of the challenges associated with metabolome profiling in complex biological samples is to generate quantitative information on the metabolites of interest. In this work, a targeted metabolome analysis strategy is presented for the quantification of amine-containing metabolites. A dimethylation reaction is used to introduce a stable isotopic tag onto amine-containing metabolites followed by LC-ESI MS analysis. This labeling reaction employs a common reagent, formaldehyde, to label globally the amine groups through reductive animation. The performance of this strategy was investigated in the analysis of 20 amino acids and 15 amines by LC-ESI MS. It is shown that the labeling chemistry is simple, fast (13C-dimethylation does not show any isotope effect on either RPLC or HILIC LC, indicating that 13C-labeling is a preferred approach for relative quantification of amine-containing metabolites in different samples. The isotopically labeled 35 amine-containing analogues were found to be stable and proved to be effective in overcoming matrix effects in both relative and absolute quantification of these analytes present in a complicated sample, human urine. Finally, the characteristic mass difference provides additional structural information that reveals the existence of primary or secondary amine functional groups in amine-containing metabolites. As an example, for a human urine sample, a total of 438 pairs of different amine-containing metabolites were detected, at signal-to-noise ratios of greater than 10, by using the labeling strategy in conjunction with RP LC-ESI Fourier-transform ion cyclotron resonance MS.

Heterobidentate sulfide-tertiary amine ligands incorporating 1,2-aminothioethers derived from ephedrine and pseudoephedrine have been prepared and used successfully in the palladium-catalysed asymmetric allylic substitution reaction, giving ees of up to 89 percent. The stereoelectronic effects operating in the reactions are discussed.

N-Methyl pseudoephedrine mediated dynamic resolution of α-bromo-α-alkyl esters in nucleophilic substitution reaction has been investigated. Best results are obtained when α-bromo-α-alkyl esters 1, 4 and 5 are allowed to equilibrate before the addition of nucleophile. This simple epimerization-substitution sequence provides a practical protocol for asymmetric syntheses of α-amino acid derivatives 2, 7 and 8 up to 98:2 enantiomeric ratio.

Enantiomerically pure β-hydroxyalkyl and β-aminoalkyl ferrocenyl sulfides have been synthesized in good yields from mercaptoferrocene and amino alcohol derivatives. Primary β-aminoalkyl sulfides allowed the synthesis of tetrahydro-1,4-thiazepines containing the ferrocene moiety with good diastereoselectivity and β-iminoalkyl sulfides. Some of these derivatives have successfully been employed as ligands for palladium-catalyzed allylic substitution, with asymmetric induction of up to 99% ee. ( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

The present invention provides an advantageous method for producing an optically active chrysanthemic acid. Disclosed is a method for producing an optically active chrysanthemic acid whose trans isomer ratio and optical purity are improved, which comprises reacting chrysanthemic acid having a trans isomer ratio of not less than 50% and an optical purity of not less than 10% e.e. with an optically active organic amine to optically resolve said chrysanthemic acid.

Oxazolidinones are obtained by the cyclization of mesylates derived from N-Boc-β-Aminoalcohols. Hydrolysis of the N-Boc-Oxazolidinones regenerates the protected aminoalcohols with inverted configuration at the hydroxy group. (C) 2000 Elsevier Science Ltd.

The reductive cleavage of cyclic aminol ethers to give N-alkylamino-derivatives in very high yields can be achieved using chlorotrimethylsilane in the presence of sodium cyanoborohydride: in the case of cyclic aminol ethers derived from formaldehyde the Eschweiler-Clarke reaction can be carried out in formic acid heated under reflux in the absence of formaldehyde.

The present invention provides an advantageous method for producing an optically active chrysanthemic acid. Disclosed is a method for producing an optically active chrysanthemic acid whose trans isomer ratio and optical purity are improved, which comprises reacting chrysanthemic acid having a trans isomer ratio of not less than 50% and an optical purity of not less than 10% e.e. with an optically active organic amine to optically resolve said chrysanthemic acid.

The reactivity of (-)-ephedrine (2) and (+)-norpseudoephedrine (3) towards the amid-acetals 1 a/b has been studied.Both 2 and 3 were acetylated resp. formylated at first at the amino group.Nevertheless, derivatives of 2 and 3 possessing a trisubstituted amino group react with 1 a in a sigmatropic rearrangement to ortho substituted dimethylcarbamoylmethyl derivatives.By subsequent reduction with lithiumaluminiumhydride the aromatic compounds 8, 13, and 18 with two aminoethyl groups are easily available.In contrast to these results 1 b did not furnish any rearrangement products. Keywords. (-)-Ephedrine; (+)-Norpseudoephedrine; N,N-Dimethylacetamid-dimethylacetal; N,N-Dimethylformamid-dimethylacetal; Sympathomimetic effects; Sigmatropic rearrangements.

The preparation of a rationally designed catalyst system derived from norephedrine is reported.The key stereodirective element emanates from a chromium tricarbonyl group complexed to one face of the aryl ring.The catalysts mediate the addition of diethyl zinc to a variety of aldehydes with extremely high enantioselectivity.Key Words: enantioselective catalyst; norephedrine; arene chromium tricarbonyl; diethyl zinc; chiral 1,2-addition

Phenylphosphinic acid and dialkylsulfoxides are found to be alternative reagents for respectively the reducing reagent (formic acid) and the alkylating reagent (aldehyde) currently used for secondary amines N-alkylation. Primary amines do not react with this system, but phenylglycine is decarboxilated to benzylamine.

(-)-(1S,2S)-(N,O-Dimethylephedrine)tricarbonylchromium(0) (6) and (-)-(1S,2R)-(N,O-dimethylpseudoephedrine)tricarbonylchromium(0) (22) undergo completely stereoselective ortho deprotonation upon treatment with alkyllithium base, followed by addition of an electrophile.In both cases, exclusive remolval of the pro-(R)-ortho proton was confirmed by single X-ray structure analyses of the methylated products.Addition of methyllithium onto the ortho-formylated derivative of complex (6) occurs stereoselectively, the stereochemistry of the major product being confirmed by a single crystal X-ray structure determination.The results presented demonstrate an efficient transfer of chirality from a side chain onto the (arene)tricarbonylchromium(0) complex and back to a different side chain.

Vasodilating activity is exhibited by compounds having the formula STR1 wherein X can be --S--or --CH2 --; and R2 is STR2 depending upon the definition of X.

A variety of chiral auxiliaries R*OH were prepared and tested for levels of asymmetric induction control in the "Mukaiyama-aldol" reaction of chiral silyl ketene acetals.Structural features required for high levels of control are discussed.

Reduction of aldehydes and ketones with hydrosilanes proceeded in the presence of a catalytic amount of tetrabutylammonium fluoride or tris(diethylamino)sulfonium difluorotrimethylsilicate in aprotic polar solvents under mild conditions.A significant isotope effect (kH/kD = 1.50) was observed in competitive reduction of acetophenone with HSiMe2Ph and DSiMe2Ph.The reaction was of first order in the concentration of an aprotic polar solvent HMPA.Reduction of 2-methylcyclohexanone gave cis-2-methylcyclohexanol with selectivities up to 95percent.The kinetic and stereochemical results suggest that a hexavalent fluorosilicate - is involved. α-Alkoxy (acyloxy or dimethylamino) ketones were transformed to threo alcohols in high diastereoselectivities.The reduction was also applied to α-methyl-β-keto amides, RCOCH(MeCONR)2, to afford the corresponding threo alcohols in >98percent selectivity.The threo selectivity is explained in terms of the Felkin-Anh model in which interaction of carbonyl oxygen with a countercation is ideally suppressed.The threo-directed reduction was applied to (R)-1-phenyl-4-(2-tetrahydropyranyloxy)-1-penten-3-one and N-(2-benzoylpropanoyl)piperidine.The resulting threo alcohols were respectively converted into (2R,3S)-2,3-(cyclohexylidenedioxy)butanal, a key intermediate of daunosamine synthesis, and into a pharmacologically useful compound threo-N-(3-hydroxy-2-methyl-3-phenylpropyl)piperidine.

Treatment of (S)-(η6-N,N-dimethylamphetamine)Cr(CO)3, with n-butyllithium below -40 deg C gives a stable benzylic carbanion via loss of the pro-R-benzylic proton.Warming of this anion above -40 deg C gives (η6-E-β-methylstyrene)Cr(CO), via an ElcB type elimination wilhst trapping with an electrophile below -40 deg C gives benzylically functionalised amphetamines with overall retention of configuration.The use of oxodiperoxymolybdenum(pyridine)hexamtehylphosphoramide as the electrophile gives optically pure (1S,2S)-N-methylpseudoephedrine after decomplexation.

The reduction of aminoketones and aziridinoketones with zinc borohydride is highly stereoselective.The zinc atom is complexed only by nitrogen atoms of reduced molecules.There is no chelate formation with the participation of carbonyl groups.

TiCl4 mediated aldol condensations establish multiple contiguous chiral centers in an almost complete enantio- and diastereoselective way.

A practical and fairly general procedure for the kinetic resolution of β-hydroxy tertiary amines is described.It involves the selective oxidation of one enantiomer to the N-oxide by using tert-butyl hydroperoxide (TBHP) and a chiral catalyst prepared by mixing 2 parts of titanium isopropoxide (Ti(O-i-Pr)4 and 1.2 parts of either (+)- or (-)-diisopropyl tartrate (DIPT).The product N-oxide and the unreacted amino alcohol are then easily separated by trituration or organic/aqueous solvent extractions, and chromatography is avoided.The oxidations are generally run to 60percent conversion and the results for 21 different amino alcohols are given.The enantiomeric excess of the slow reacting (i.e., recovered) enantiomer of the amino alcohol often exceeds 90percent.Among the more interesting substrates are the natural product ubine (95percent ee) (18), N-methylephedrine (95percent ee) (15), N-methylpseudoephedrine (93percent ee) (16), cis-2-(dimethylamino)cyclohexanol (>95percent ee) (13), trans-2-(dimethylamino)cyclohexanol (92percent ee) (12), N-benzylbevantolol (85percent ee) (27), and N-benzylpropranolol (32percent ee) (21).The latter two examples are β-blocker precursors.One of the most important characteristics of this new route to enantiomerically pure β-hydroxy amines is its predictability.Thus, in all cases examined to date, when using (+)-DIPT the absolute configuration at the carbinol center in the slow reacting enantiomer is always the same .A study of how the titanium/tartrate ratio, water, catalyst/substrate ratio, and temperature effect this reaction is discussed.

The pro-R hydrogen of (+)-N,N-dimethylamphetamine chromium tricarbonyl can be stereospecifically substituted via sequential treatment with BunLi and an electrophile, with retention of configuration to give for example N-methylpseudoephedrine after decomplexation.

Enantioselective oxidation using TBHP and an asymmetric titanium-tartrate complex provides direct access to a variety of homochiral β-hydroxy amines.

Novel modified lithium aluminum hydride type reducing agents obtained by reacting one equivalent of lithium aluminum hydride with one equivalent of an optically active N-substituted ephedrine of the formula, STR1 (wherein R 1 is a C 1 -C 4 alkyl group or benzyl group, and Ph is phenyl group)and two equivalents of an N-substituted aniline of the formula, STR2 (wherein R 2 is C 1 -C 4 alkyl group or phenyl group, and Ph is phenyl group).This reducing agent is usable for reducing the organic compounds having a carbonyl group (ketone group or aldehyde group) in their structure into the corresponding alcohols. It is particularly useful as a reducing agent for asymmetrically reducing the unsymmetrical ketones to selectively produce either an alcohol in which the asymmetric carbon atom bonded to the hydroxy group is in R-configuration or an alcohol in which said asymmetric carbon atom is in S-configuration.

Quinidine (5) catalyzes the addition of ketene (1) to chloral (2) at -50 deg C in toluene.The β-(trichloromethyl)-β-propiolactone 3 is formed virtually optically pure (98percent enantiomeric excess).A mechanism for this reaction, accounting for the high enantiomeric excess, is proposed.Known hydrolytic procedures convert the lactone 3 to malic acid (6).By proper choice of catalyst both (R)- and (S)-malic acid can be obtained optically pure.