Enantioselective Synthesis of (R)- and (S)-α-Alkylcysteines via Phase-Transfer Catalytic Alkylation

Yeungnam University, Gyeongsan, Gyeongsangbuk-do, South Korea
The Journal of Organic Chemistry (Impact Factor: 4.72). 10/2006; 71(21):8276-8. DOI: 10.1021/jo061107t
Source: PubMed


We reported efficient enantioselective synthetic methodologies for (R)-alpha-alkylcysteines and (S)-alpha-alkylcysteines. The phase-transfer catalytic alkylation of 2-phenyl-2-thiazoline-4-carboxylic acid tert-butyl ester and 2-o-biphenyl-2-thiazoline-4-carboxylic acid tert-butyl ester, in the presence of chiral catalysts (1 or 2), gave the corresponding alkylated products, which could be hydrolyzed to provide (R)-alpha-alkylcysteines (67->99% ee) and (S)-alpha-alkylcysteines (66-88% ee), respectively.

16 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: [67174-25-8] C27H31ClN2O2 (MW 451.01) InChI = 1S/C27H31N2O2.ClH/c1-3-20-18-29(17-19-7-5-4-6-8-19)14-12-21(20)15-26(29)27(30)23-11-13-28-25-10-9-22(31-2)16-24(23)25;/h3-11,13,16,20-21,26-27,30H,1,12,14-15,17-18H2,2H3;1H/q+1;/p-1/t20-,21-,26-,27+,29+;/m0./s1InChIKey = JYDIJFKNXHPWBJ-GOGFHWEMSA-M(chiral, nonracemic quaternary ammonium salt; catalyst for a variety of phase transfer reactions under basic conditions1)Alternate Names: Quibec; BQC.Physical Data: mp 180–181 °C, [α]19D −235.5° (c = 1.5, H2O);2 monohydrate: mp 169–172 °C (dec), [α]d −212.5° (c = 0.5, EtOH).3Solubility: freely sol H2O, alcohols, acetone; slightly sol EtOAc; sparingly sol CHCl3.4Form Supplied in: solid.Purification: recrystallized from absolute EtOH.3
    Encyclopedia of Reagents for Organic Synthesis, 09/2007; , ISBN: 0471936235
  • [Show abstract] [Hide abstract]
    ABSTRACT: A review on the asymmetric reactions with various types of chiral quaternary ammonium salts which is used as the phase-transfer catalysts is presented which shows off the variations of the molecular designs and synthetic applications. The topics discussed include the alkylation, the Michael addition, the aldol reaction, Mannich reaction, Darzens reaction, the Neber rearrangement, epoxidation, aziridination, dihydroxylation, fluorination, and the Strecker reaction. Chiral phase-transfer catalysts maybe developed with the reliance on the molecular design of both the natural product-derived and purely synthetic chiral quaternary ammonium salts. This development provides new synthetic opportunities by expanding the applicability of this catalysis in modern organic synthesis.
    Chemical Reviews 04/2008; 107(12):5656-82. DOI:10.1021/cr068368n · 46.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: IntroductionAlkylationMichael AdditionAldol ReactionMannich ReactionNeber RearrangementEpoxidationStrecker ReactionConclusions References
Show more


16 Reads
Available from