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.

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