Facial-Selective Allylation of Methyl Ketones for the Asymmetric Synthesis of Tertiary Homoallylic Ethers

Abstract

The stereoselective allylation of methyl ketones is described to give tertiary homoallylic ethers, which can easily be transformed into homoallylic alcohols by a Birch reduction. Reaction of methyl ketones 4 with allylsilane 5 in the presence of the chiral TMS ether 3a and a catalytic amount of trifluoromethanesulfonic acid led to homoallylic ethers 6 in high yield with a selectivity of 9:1 to >20:1. The TMS ether 3a was prepared from inexpensive mandelic acid, which is commercially available in both enantiomeric forms, in four steps.

Key words

allylations - allylsilannes - amino alcohols - asymmetric synthesis - Birch reduction - homoallylic alcohols

References

• 1a Catalytic Asymmetric Synthesis   Ojima I. Wiley-VCH; New York: 2000. 
• 1b Marshall JA. Chem. Rev.  1996,  96:  31 
• 1c Yanagisawa A. In Comprehensive Asymmetric Catalysis   Vol. 2:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer; Berlin: 1999. 
• 2a Denmark SE. Fu J. Chem. Rev.  2003,  103:  2763 
• 2b Fürstner A. Voigtländer D. Synthesis  2000,  959 
• 2c Batey RA. Thadani AN. Smil DV. Lough AJ. Synthesis  2000,  990 
• 2d Yamamoto Y. Asao N. Chem. Rev.  1993,  93:  2207 
• 2e Duthaler RO. Hafner A. Chem. Rev.  1992,  92:  807 
• 2f Hoffmann RW. Weidmann U. Chem. Ber.  1985,  118:  3966 
• 2g Brown HC. Jadhav PK. Bhat KS. J. Am. Chem. Soc.  1988,  110:  1535 
• 2h Brown HC. Racherla US. Liao Y. Khanna VV. J. Org. Chem.  1992,  57:  6608 
• 3a Riediker M. Duthaler RO. Angew. Chem., Int. Ed. Engl.  1989,  28:  494 
• 3b Jadhav PK. Barth KS. Perumal PT. Brown HC. J. Org. Chem.  1986,  51:  432 
• 4a Kii S. Maruoka K. Chirality  2003,  15:  68 
• 4b Waltz KM. Gavenonis J. Walsh PJ. Angew. Chem. Int. Ed.  2002,  41:  3697 
• 4c Casolari S. D’Addario D. Tagliavini E. Org. Lett.  1999,  1:  1061 
• 5a Tietze LF. Wulff C. Wegner C. Schuffenhauer A. Schiemann K. J. Am. Chem. Soc.  1998,  120:  4276 
• 5b Tietze LF. Schiemann K. Wegner C. Wulff C. Chem. Eur. J.  1996,  2:  1164 
• 5c Tietze LF. Dölle A. Schiemann K. Angew. Chem., Int. Ed. Engl.  1992,  31:  1372 
• 6a Tietze LF. Modi A. Med. Res. Rev.  2000,  4:  304 
• 6b Tietze LF. Chem. Rev.  1996,  96:  115 
• 6c Tietze LF. Beifuss U. Angew. Chem., Int. Ed. Engl.  1993,  32:  131 
• 7a Tietze LF. Weigand B. Völkel L. Wulff C. Bittner C. Chem. Eur. J.  2001,  7:  161 
• 7b Tietze LF. Völkel L. Wulff C. Weigand B. Bittner C. McGrath P. Johnson K. Schäfer M. Chem. Eur. J.  2001,  7:  1304 
• 7c Tietze LF. Wegner C. Wulff C. Chem. Eur. J.  1999,  5:  2885 
• 7d Tietze LF. Schiemann K. Wegner C. Wulff C. Chem. Eur. J.  1998,  4:  1862 
• 7e Tietze LF. Wegner C. Wulff C. Eur. J. Org. Chem.  1998,  4:  1639 
• 7f Tietze LF. Wegner C. Wulff C. Synlett  1996,  471 
• 7g Tietze LF. Schiemann K. Wegner C. J. Am. Chem. Soc.  1995,  117:  5851 
• 8 Tietze LF. Völkel L. Angew. Chem. Int. Ed.  2001,  40:  901 
• 9 Hossain MT. Timberlake JW. J. Org. Chem.  2001,  66:  6282