2-Amino-3-benzyl-5-phenyl- -bromid

An alternative synthesis of this compound which avoids UAIH4 involves N-benzylation of commercially available (e. g., Aldrich Chemical Company, Inc.) (S)-2-amino-3-phenylpropanol as follows A mixture of 3.78 g (25 mmol) of (S)-2-amino-3-phenyl-1-propanol and 6.91 g (50 mmol) of potassium carbonate in 50 mL of 96% ethanol and 10 mL of water is brought to reflux temperature. To this stirred, two-phase mixture is added dropwise 10.69 g (62.5 mmol) of benzyl bromide. The vigorously stirred mixture is heated at reflux for an additional 0.5 hr and cooled to room temperature, and 30 mL of water are added. The product is extracted three times with... 

AUyl-2-benzyl- -bromid 938 3-Allyl-2-phenyl- -triodid 938 3-Amino-2-dimethylamino- ... 

A Strategy similar to that shown in Scheme 4.8 employs a Grignard addition to a cyclic a-bromoglycine derivative. As shown in Scheme 4.9, elimination of bromide affords an iminium ion that is selectively attacked on the Si-face, opposite the two phenyl groups [100]. Reductive cleavage of the benzylic C-N and C-0 bonds provides ready access to amino acids. 

Benzyl bromide Toluene, a-bromo- (8) Benzene, (bromomethyl)- (9) (100-39-0) (S)-2-(N,N-Dlbenzylamino)-3-phenyl-1-propanol Benzenepropanol, p-[bis(phenylmethyl)amino]-, (S)- (12) (111060-52-7)... 

Asymmetric PTC is an important method in the synthesis of a-alkyl and a-amino acids. Belokon et al. [7] reported that the compound (47 ,57 )-2,2-dimethyl-Q ,Q ,Q , Q -tetra-phenyl-l,3-dioxolane-4,5-dimethanol (TADDOL) was used to catalyze the C-alkylation of C-H acids with alkyl halides to the asymmetric synthesis of a-methyl-substituted a-amino acids under PTC conditions. The alkylations of the substrate C-H acids with benzyl bromide or allyl bromide were conducted in dry toluene at ambient temperature with NaH or solid NaOH as base and TADDOL as a chiral promoter. The type of base is important in the asymmetric C-alkylation of C-H acids. 

---