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key term - (S)-2-amino-2′-hydroxy-1,1′-binaphthyl

Citation:

Definition

(S)-2-amino-2′-hydroxy-1,1′-binaphthyl is a chiral organic compound with a binaphthyl backbone and an amino group at the 2-position and a hydroxyl group at the 2'-position. This compound is an important intermediate in the synthesis of various amino acids and other biologically active molecules.

5 Must Know Facts For Your Next Test

  1. The (S)-configuration of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl refers to the absolute stereochemistry of the molecule, which is an important factor in its use as a chiral auxiliary.
  2. This compound is commonly used in the synthesis of $\alpha$-amino acids via the Strecker amino acid synthesis, where it acts as a chiral template to control the stereochemistry of the final product.
  3. The binaphthyl backbone of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl provides rigidity and a defined chiral environment that can effectively transfer chirality to the substrate.
  4. The amino and hydroxyl functional groups on (S)-2-amino-2′-hydroxy-1,1′-binaphthyl allow for further derivatization and incorporation into larger synthetic schemes.
  5. Enantiopure (S)-2-amino-2′-hydroxy-1,1′-binaphthyl is commonly prepared via resolution of the racemic mixture or asymmetric synthesis starting from 2-naphthol.

Review Questions

  • Explain the role of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl in the synthesis of $\alpha$-amino acids.
    • In the Strecker amino acid synthesis, (S)-2-amino-2′-hydroxy-1,1′-binaphthyl acts as a chiral auxiliary to control the stereochemistry of the final $\alpha$-amino acid product. The rigid binaphthyl backbone and the presence of the amino and hydroxyl groups allow (S)-2-amino-2′-hydroxy-1,1′-binaphthyl to effectively transfer its chirality to the substrate, resulting in the formation of the desired enantiomer of the amino acid.
  • Describe the structural features of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl that contribute to its utility as a chiral auxiliary.
    • The key structural features of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl that make it a useful chiral auxiliary are: 1) the binaphthyl backbone, which provides rigidity and a defined chiral environment; 2) the amino group at the 2-position, which allows for further derivatization; and 3) the hydroxyl group at the 2'-position, which also enables additional modifications. These features allow (S)-2-amino-2′-hydroxy-1,1′-binaphthyl to effectively transfer its chirality to the substrate during asymmetric synthesis reactions.
  • Analyze the importance of enantiopurity in the use of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl as a chiral auxiliary, and discuss the methods commonly used to obtain the pure (S)-enantiomer.
    • The enantiopurity of (S)-2-amino-2′-hydroxy-1,1′-binaphthyl is crucial for its successful use as a chiral auxiliary, as any contamination with the opposite (R)-enantiomer would lead to the formation of unwanted stereoisomers of the target molecule. To obtain the pure (S)-enantiomer, researchers commonly employ resolution techniques, such as fractional crystallization or chromatographic separation, to separate the racemic mixture. Alternatively, asymmetric synthesis methods starting from 2-naphthol can be used to directly produce enantiopure (S)-2-amino-2′-hydroxy-1,1′-binaphthyl. Ensuring the high enantiopurity of this chiral auxiliary is essential for achieving the desired stereochemical outcome in the synthesis of $\alpha$-amino acids and other important compounds.