S -4-Benzyl-2-oxazolidinone

In a similar manner, aldehydes can also be enantioselectively alkylated by this procedure. However, the enantiomeric excess obtained is much lower (47%). A special application of this method is the enantioselective alkylation of aldehydes for the construction of quaternary stereogenic centers. An example is the formation of the chiral quaternary carbon in 4-methyl-4-phenylcyclohex-2-en-1-one in high enantiomeric excess using this methodology (eq 4).  

Chiral Cuprate Reagents. This chiral amine has also found application in asymmetric conjugate addition of copper azaeno-lates to cyclic enones. Lithium azaenolates of optically active acetone imines have been used in the preparation of chiral cuprate reagents. However, the asymmetric induction is low (17-28% ee) when this amine is employed (eq 5).  

Eduardo A. Veliz Joseph P. Konopelski University of California, Santa Cruz, CA, USA 

Form Supplied in white crystalline solid commercially available. 

Handling, Storage, and Precautions no special handling or storage precautions are necessary. There is no known toxicity. It may be harmful by inhalation, ingestion, or skin absorption and may cause skin or eye irritation. 

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Figure 19 Graph of Corrected Retention Volume of the (S) 4-Benzyl-2-oxazolidinone against the Reciprocal of the Volume Fraction of Ethanol...

Related Reagents. (25, 45)-3-Benzoyl-2-r-butyl-4-methyl-l,3-oxazolidin-5-one (,S )-4-Benzyl-2-oxazolidinone (R,R)-2-t-Butyl-5-methyl-l,3-dioxolan-4-one 10,2-(2amphorsultam 10-Dicyclohexylsulfonamidoisobomeol (R,/J)-2,5-Dimethylboro-lane Ethyl 3-Hydroxybutanoate 2-Hydroxy-l,2,2-triphenyl-ethyl Acetate (5)-4-Benzyl-2-oxazolidinone (RJi)-l,2-Dipheny 1-1,2-diaminoethane NA( -Bis[3,5-bis(trifluoromethyl)-benzenesulfonamide] 2,2,6-Trimethy 1-4//-1,3-dioxin-4-one. 

We (Novartis) reported ] an enantioselective synthesis of (2S,2 71)- zyf/iro-methylphenidate (3) utilizing Evans (S)-4-benzyl-2-oxazolidinone chiral auxiliary to control the diastereofacial selectivity in the hydrogenation of enamine intermediate (65 Scheme 16). Acylation of (S)-4-benzyl-V-phenylace-tyl-2-oxazolidinone (61) with the mixed anhydride 63, followed by deprotection of the V-Boc group with TFA, and neutralization of the reaction mixture with NaHCOs afforded the enamine intermediate 65. Hydrogenation of enamine 65 with 10% Pd-C in ethyl acetate furnished 66 in 95% yield with an excellent diastereoselectivity (97 5). Treatment of 66 with methanol in the presence of EnR afforded the desired... 

Acetate ( 5 ,55)-4-Methox)methyl-2-methyl-5-phenyl-2-oxa-zoline (S)-4-Benzyl-2-oxazolidinone. 

Related Reagents. (S)-4-Benzyl-2-oxazolidinone 10,2-Camphorsultam (/ )-(+)-f-Butyl 2-(p-Tolylsulfinyl)propionate 10-Dicyclohexylsulfonamidoisobomeol Diisopinocampheyl-boron Trifluoromethanesulfonate (R,R)-2,5-Dimethylborolane 2,6-Dimethylphenyl Propionate Ethyl 2-(Methyldiphenylsilyl)-propanoate a-Methyltoluene-2,a-sultam 3-Propionylthiazoli-dine-2-thione (/ ,/ )-1,2-Diphenyl-1,2-diaminoethane iV,iV -Bis-[3,5-bis(trifluoromethyl)benzenesulfonamide] 1,1,2-Triphenyl-1,2-ethanediol. 

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