Get access

Catalysis of Enantioselective Strecker Reaction in the Synthesis of D-Homophenylalanine Using Recyclable, Chiral, Macrocyclic MnIII–Salen Complexes

Authors

  • S. Saravanan,

    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author
  • Dr. Noor-ul H. Khan,

    Corresponding author
    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    • Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author
  • Prasanta K. Bera,

    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author
  • Dr. Rukhsana I. Kureshy,

    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author
  • Dr. Sayed H. R. Abdi,

    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author
  • Prathibha Kumari,

    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author
  • Dr. Hari C. Bajaj

    1. Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 021, Gujarat (India), Fax: (+91) 0278-2566970
    Search for more papers by this author

Abstract

A convenient approach to the asymmetric Strecker reaction was established by synthesizing chiral, mono- and dinuclear, macrocyclic MnIII–salen complexes possessing achiral and chiral linkers (trigol, piperazine, and diethyl tartarate). This group of macrocyclic complexes has emerged as improved metal-based catalysts for the enantioselective Strecker reaction of aldimines, giving high enantioselectivity (up to 99 %) for a wide range of substrates. The macrocylic complex 6 a with trigol linker works very well with TMSCN (trimethylsilyl cyanide) as a source of cyanide, using 4-phenyl pyridine N-oxide (4-PPyNO) as a co-catalyst in toluene at −40 °C. However, the macrocyclic complex 6 b with diethyl tartarate as a linker affected excellent chiral induction for both aromatic and aliphatic imines with a safer cyanide source (ethyl cyanoformate) in toluene at −20 °C in the presence of N,N-diisopropylimine as a co-catalyst. Complexes 6 a and 6 b used in the present study were recoverable and recyclable (five times) with retention of their performance at gram level. The kinetic study with complex 6 a for the enantioselective Strecker reaction of N-benzyl benzylimine revealed a first-order dependence on catalyst, substrate, and TMSCN concentration. This protocol with catalyst 6 b was further extended for the synthesis of D-homophenyl alanine, an important analogue in factor Xa inhibitors.

Ancillary