Preparation of Enantioenriched Axially Chiral Anilides via [2+2+2] Cycloaddition of 1,6-Diynes with Trimethylsilylynamides

Abstract

The rhodium-catalyzed enantioselective [2+2+2] cycloaddition of 1,6-diynes with trimethylsilylynamides provides enantio­enriched axially chiral anilides in poor to good yields with good to excellent enantioselectivity. Trimethylsilylynamides can be readily prepared­ in two steps starting from commercially available bis(trimethylsilyl)acetylene.

Key words

anilides - diynes - BINAP - rhodium - ynamides

References

• 1 For the pioneering work on axially chiral N-substituted ortho-tert-butyl anilides, see: Curran DP. Qi H. Geib SJ. DeMello NC. J. Am. Chem. Soc.  1994,  116:  3131 
• For the synthesis of axially chiral anilides, see:
• 2a Kitagawa O. Izawa H. Sato K. Dobashi A. Taguchi T. Shiro M. J. Org. Chem.  1998,  63:  2634 
• 2b Hughes AD. Price DA. Simpkins NS. J. Chem. Soc., Perkin Trans. 1  1999,  1295 
• 2c Kondo K. Fujita H. Suzuki T. Murakami Y. Tetrahedron Lett.  1999,  40:  5577 
• 2d Ates A. Curran DP. J. Am. Chem. Soc.  2001,  123:  5130 
• For the asymmetric synthesis of axially chiral anilides through enantiotopic deprotonation, see:
• 3a Hata T. Koide H. Taniguchi N. Uemura M. Org. Lett.  2000,  2:  1907 
• 3b Koide H. Hata T. Yoshihara K. Kamikawa K. Uemura M. Tetrahedron  2004,  60:  4527 
• 3c Bennett DJ. Pickering PL. Simpkins NS. Chem. Commun.  2004,  1392 
• 4 For the stereoselective synthesis of axially chiral N-aryl indoles, see: Kamikawa K. Kinoshita S. Matsuzaka H. Uemura M. Org. Lett.  2006,  8:  1097 
• 5a Kitagawa O. Kohriyama M. Taguchi T. J. Org. Chem.  2002,  67:  8682 
• 5b Terauchi J. Curran DP. Tetrahedron: Asymmetry  2003,  14:  587 
• 6a Kitagawa O. Takahashi M. Yoshikawa M. Taguchi T. J. Am. Chem. Soc.  2005,  127:  3676 
• 6b Kitagawa O. Yoshikawa M. Tanabe H. Morita T. Takahashi M. Dobashi Y. Taguchi T. J. Am. Chem. Soc.  2006,  128:  12923 
• 7 For our first report on the cationic rhodium(I)/modified-BINAP-catalyzed inter- and intramolecular [2+2+2] cycloadditions, see: Tanaka K. Shirasaka K. Org. Lett.  2003,  5:  4697 
• For the enantioselective synthesis of axially chiral biaryls, see:
• 8a Tanaka K. Nishida G. Wada A. Noguchi K. Angew. Chem. Int. Ed.  2004,  43:  6510 
• 8b Tanaka K. Nishida G. Ogino M. Hirano M. Noguchi K. Org. Lett.  2005,  7:  3119 
• 8c Tanaka K. Wada A. Noguchi K. Org. Lett.  2005,  7:  4737 
• 8d Nishida G. Suzuki N. Noguchi K. Tanaka K. Org. Lett.  2006,  8:  3489 
• 8e Tanaka K. Suda T. Noguchi K. Hirano M. J. Org. Chem.  2007,  72:  2243 
• 8f Nishida G. Noguchi K. Hirano M. Tanaka K. Angew. Chem. Int. Ed.  2007,  46: 3951
• 8g Tanaka K. Otake Y. Wada A. Hirano M. Org. Lett.  2007,  9:  2203 
• 9 For the enantioselective synthesis of axially chiral spiranes, see: Wada A. Noguchi K. Hirano M. Tanaka K. Org. Lett.  2007,  9:  1295 
• For the synthesis of cyclophanes, see:
• 10a Tanaka K. Toyoda K. Wada A. Shirasaka K. Hirano M. Chem. Eur. J.  2005,  11:  1145 
• 10b Tanaka K. Sagae H. Toyoda K. Noguchi K. Eur. J. Org. Chem.  2006,  3575 
• For enantioselective synthesis of planar-chiral metacyclophanes, see:
• 10c Tanaka K. Sagae H. Toyoda K. Noguchi K. Hirano M. J. Am. Chem. Soc.  2007,  129:  1522 
• For the enantioselective construction of central chiralities, see:
• 11a Tanaka K. Wada A. Noguchi K. Org. Lett.  2006,  8:  907 
• 11b Tanaka K. Suzuki N. Nishida G. Eur. J. Org. Chem.  2006,  3917 
• 11c Tanaka K. Osaka T. Noguchi K. Hirano M. Org. Lett.  2007,  9:  1307 
• 11d Tanaka K. Nishida G. Sagae H. Hirano M. Synlett  2007,  1426 
• 12 Tanaka K. Takeishi K. Noguchi K. J. Am. Chem. Soc.  2006,  128:  4586 
• 13 Stang PJ. In Modern Acetylene Chemistry   Stang PJ. Diederich F. Wiley-VCH; Weinheim: 1995.  p.67 
• 14 Martinez-Esperón MF. Rodriguez D. Castedo L. Saá C. Org. Lett.  2005,  7:  2213 
• 15 For a recent review of ynamides, see: Zificsak CA. Mulder JA. Hsung RP. Rameshkumar C. Wei L.-L. Tetrahedron  2001,  57:  7575 
• 16 For the RhCl(PPh₃)₃-catalyzed [2+2+2] cycloadditions of ynamides leading to amide-substituted chiral biaryls, see: Tracey MR. Oppenheimer J. Hsung RP. J. Org. Chem.  2006,  71:  8629 
• For the RhCl(PPh₃) ₃-catalyzed [2+2+2] cycloadditions of ynamides for the synthesis of nitrogen heterocycles, see:
• 17a Witulski B. Stengel T. Angew. Chem. Int. Ed.  1999,  38:  2426 
• 17b Witulski B. Alayrac C. Angew. Chem. Int. Ed.  2002,  41:  3281