Asymmetric Synthesis of Both Enantiomers of α-Trifluoromethyl Substituted Homoallylamine

Abstract

An efficient asymmetric synthesis of both enantiomers of α-trifluoromethylated homoallylamine via nucleophilic allylation of trifluoroacetaldehyde SAMP- or RAMP-hydrazone, followed by benzoylation and SmI₂-promoted nitrogen-nitrogen single bond cleavage is described.

Key words

asymmetric synthesis - fluorine - hydrazone - allylation - amines

References

• For recent reviews on allylic metals, see:
• 1a Yamamoto Y. Asao N. Chem. Rev.  1993,  93:  2207 
• 1b Kleinman EF. Volkmann RA. In Comprehensive Organic Synthesis   Vol. 2:  Trost BM. Fleming I. Pergamon; New York: 1991.  p.975 
• For reviews on the 1,2-addition to the carbon-nitrogen double bond, see:
• 2a Denmark SE. Nicaise OJ.-C. Chem. Commun.  1996,  999 
• 2b Enders D. Reinhold U. Tetrahedron: Asymmetry  1997,  8:  1895 
• 2c Bloch R. Chem. Rev.  1998,  98:  1407 
• 2d Kobayashi S. Ishitani H. Chem. Rev.  1999,  99:  1069 
• 2e Merino P. Franco S. Merchan FL. Tejero T. Synlett  2000,  442 
• 2f Alvaro G. Savoia D. Synlett  2002,  651 
• For a review on functionalized α-trifluoromethylated amines using the sulfinyl or 1-phenylethyl group as chiral auxiliary, see:
• 3a Bravo P. Zanda M. In Enantiocontrolled Synthesis of Fluoroorganic Compounds   Soloshonok VA. Wiley; Chichester: 1999.  p.107 
• 3b Bravo P. Bruche L. Crucianell M. Viani F. Zanda M. In Asymmetric Fluoroorganic Chemistry: Synthesis, Application, and Future Directions   Ramachandran PV. American Chemical Society; Washington DC: 1999.  p.98 
• 3c Soloshonok VA. Bravo P. Bruche L. Crucianell M. Viani F. Zanda M. In Asymmetric Fluoroorganic Chemistry: Synthesis, Application, and Future Directions   Ramachandran PV. American Chemical Society; Washington DC: 1999.  p.74 
• 3d Pirkle WH. Hauske JR. J. Org. Chem.  1977,  42:  2436 
• 3e Wang Y. Mosher HS. Tetrahedron Lett.  1991,  32:  987 
• 3f Soloshonok VA. Ono T. J. Org. Chem.  1997,  62:  3030 
• 3g Ishii A. Higashiyama K. Mikami K. Synlett  1997,  1381 
• 3h Ishii A. Miyamoto F. Higashiyama K. Mikami K. Chem. Lett.  1998,  119 
• 3i Ishii A. Miyamoto F. Higashiyama K. Mikami K. Tetrahedron Lett.  1998,  39:  1199 
• 3j Prakash GKS. Mandal M. Olah GA. Angew. Chem., Int. Ed.  2001,  40:  589 
• 3k Prakash GKS. Mandal M. Olah GA. Org. Lett.  2001,  3:  2847 
• 3l Gong Y. Kato K. Tetrahedron: Asymmetry  2001,  12:  2121 
• 3m Demir AS. Sesenoglu O. Gerçek-Arkin Z. Tetrahedron: Asymmetry  2001,  12:  2309 
• 4 For the nucleophilic allylation of achiral trifluoromethylated ketoimines, see: Felix C. Laurent A. Lesniak S. Mison P. J. Chem. Res., Synop.  1991,  32 
• For allylation of chiral trifluoromethylated aminal, see:
• 5a Billard T. Langlois BR. J. Org. Chem.  2002,  67:  997 
• 5b Lebouvier N. Laroche C. Huguenot F. Brigaud T. Tetrahedron Lett.  2002,  43:  2827 
• 6a Enders D. Funabiki K. Org. Lett.  2001,  3:  1575 
• 6b Enders D. Faure S. Potthoff M. Runsink J. Synthesis  2001,  2307 
• 6c Enders D. Potthoff M. Raabe G. Runsink J. Angew. Chem. Int. Ed.  1997,  36:  2362 
• 6d For a recent review on the SAMP-/RAMP-hydrazone method, see: Job A. Janeck CF. Bettray W. Peters R. Enders D. Tetrahedron  2002,  58:  2253 
• 7 Manabe K. Oyamada H. Sugita K. Kobayashi S. J. Org. Chem.  1999,  64:  8025 
• For the allylation of fluorine-free aldehyde SAMP-/RAMP- or other hydrazones, see:
• 8a Enders D. Schankat J. Klatt M. Synlett  1994,  795 
• 8b Friestad GK. Ding H. Angew. Chem., Int. Ed.  2001,  40:  4491 

9

For the SmI₂-induced cleavage of the nitrogen-nitrogen single bond, see Ref. [6a]