Kano T, Sakamoto R, Akakura M, Maruoka K. Stereocontrolled synthesis of vicinal diamines by organocatalytic asymmetric Mannich reaction of N-protected aminoacetaldehydes: formal synthesis of (-)-agelastatin A.
J Am Chem Soc 2012;
134:7516-20. [PMID:
22486203 DOI:
10.1021/ja301120z]
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Abstract
The 1,2-diamine (vicinal diamine) motif is present in a number of natural products with interesting biological activity and in many chiral molecular catalysts. The efficient and stereocontrolled synthesis of enantioenriched vicinal diamines is still a challenge to modern chemical methodology. We report here both syn- and anti-selective asymmetric direct Mannich reactions of N-protected aminoacetaldehydes with N-Boc-protected imines catalyzed by proline and the axially chiral amino sulfonamide (S)-3. This organocatalytic process represents the first example of a Mannich reaction using Z- or Boc-protected aminoacetaldehyde as a new entry of α-nitrogen functionalized aldehyde nucleophile in enamine catalysis. The obtained optically active vicinal diamines are useful chiral synthons as exemplified by the formal synthesis of (-)-agelastatin A.
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