70113-32-5Relevant academic research and scientific papers
Asymmetric synthesis of α-(heteroaryl)alkylamines and α-amino acids via nucleophilic 1,2-addition of lithiated heterocycles to aldehyde SAMP-hydrazones
Enders, Dieter,Del Signore, Giuseppe,Raabe, Gerhard
, p. 492 - 518 (2013/08/23)
The asymmetric synthesis of α-(heteroaryl)alkylamines was accomplished by employing a diastereoselective nucleophilic 1,2-addition of lithiated aromatic heterocycles to aldehyde SAMP-hydrazones, followed by BH 3·THF or SmI2 promoted removal of the chiral auxiliary. The CBz or benzoyl-protected amines were obtained in good yields (40%-78%) and excellent enantiomeric excesses (ee = 88%-99%). The methodology can be applied to the synthesis of highly enantioenriched α-amino acids (ee = 90%-99%). TUeBITAK.
First asymmetric synthesis of (un)substituted bridged tetrahydro-2-benzazepines
Dumoulin, David,Lebrun, Stephane,Couture, Axel,Deniau, Eric,Grandclaudon, Pierre
scheme or table, p. 195 - 201 (2010/05/02)
A new and flexible route for the asymmetric synthesis of a variety of alkylated bridged tetrahydro-2-benzazepines has been developed. The key steps are the highly diastereoselective Michael addition of metalated SAMP-hydrazones to α,β-unsaturated esters combined with cyclomethylenation/Mitsunobu coupling reactions to secure the formation of the seven-membered azaheterocycle and of the bridged unit, respectively.
Asymmetric synthesis of 3- or 4-alkyl or arylbenzo[c]azepines
Dumoulin, David,Lebrun, Stephane,Couture, Axel,Deniau, Eric,Grandclaudon, Pierre
experimental part, p. 1903 - 1911 (2010/02/27)
Two flexible routes for the stereoselective synthesis of a variety of 3- or 4-alkylated or arylated tetrahydrobenzazepines have been developed. The key steps are the highly diastereoselective metallation/alkylation reaction and 1,2-addition processes applied to stereopure SAMP hydrazones combined with a cyclomethylenation reaction.
Regio- and enantioselective synthesis of α-silyl aldehydes and ketones via SAMP/RAMP hydrazones
Enders, Dieter,Lohray, Braj B.,Burkamp, Frank,Bhushan, Vidya,Hett, Robert
, p. 189 - 200 (2007/10/03)
An efficient, highly regio- and enantioselective methodology for the synthesis of α-silyl aldehydes and ketones 2 and 6 using two different procedures was developed. Direct α-silylation of the azaenolates derived from SAMP/RAMP hydrazones 3 with various silyl trifluoromethanesulfonates resulted after oxidative removal of the chiral auxiliary in highly enantiomerically enriched α-silyl aldehydes and ketones (R)- or (S)-2. Alternatively, hydrazones 5 derived from acetaldehyde or methyl ketones were initially α-silylated followed by highly diastereoselective α-alkylation with suitable electrophiles. The latter variant allows the regiocontrolled synthesis of α-silyl ketones (S)-6 with high enantiomeric purity, not available by direct α-silylation of unsymmetrical ketone hydrazones. The absolute configuration of the resultant α-silyl carbonyl compounds 2 and 6 was derived from earlier mechanistic investigations of electrophilic substitutions via deprotonated SAMP/RAMP hydrazones and was unambiguously assigned by X-ray-crystallographical analysis of the α-silyl-SAMP hydrazone (S,R)-4c. VCH Verlagsgesellschaft mbH, 1996.
ASYMMETRIC MICHAEL ADDITIONS VIA SAMP-/RAMP-HYDRAZONES ANTI-DIASTEREO- AND ENANTIOSELECTIVE SYNTHESIS OF 3,4-DISUBSTITUTED 5-OXO-ALKANOATES
Enders, Dieter,Papadopoulos, Kyriakos,Rendenbach, Beatrice E.M.,Appel, Rolf,Knoch, Falk
, p. 3491 - 3494 (2007/10/02)
An efficient and highly anti-diastereo-(de=90-100percent) and enantioselective (ee=92-100percent) synthesis of 3,4-disubstituted 5-oxo-alkanoates 3 in good overall chemical yields is described.The procedure involves the asymmetric Michael addition of aldehydes or ketones to enoates via their lithiated SAMP-/RAMP-hydrazones.Both enantiomers are accessible at will.
