A Practical Synthesis of α,β-Unsaturated Imides, Useful Substrates for Asymmetric Conjugate Addition Reactions

Advanced Synthesis and Catalysis

Volumn 344, Issue 9, 2002, Pages 953-956

  Goodman, Steven N ^a   Jacobsen, Eric N ^a  

^a HARVARD UNIVERSITY   (United States)

Author keywords

Asymmetric catalysis; Horner Wadsworth Emmons reactions; Imides; Synthetic methods; Wittig reactions

Indexed keywords

EID: 0141747457     PISSN: 16154150     EISSN: None     Source Type: Journal    
DOI: 10.1002/1615-4169(200210)344:9<953::AID-ADSC953>3.0.CO;2-A     Document Type: Review

References (11)

1. J. K. Myers, E. N. Jacobsen, J. Am. Chem. Soc. 1999, 121, 8959.
2. Q. Chen, G. M. Sammis, M. S. Taylor, E. N. Jacobsen, manuscripts in preparation.
3. An alternative synthesis of β-aryl-α,β-unsaturated imides has been reported, involving reaction of α,β-unsaturated acid chlorides and the sodium salt of benzamide. This procedure is convenient for readily available acid chlorides, see: Y. S. Laxmi, D. S. Iyengar, J. Chem. Soc. Perkin Trans, 1 1995, 3043.
4. J. B. Polya, T. M. Spotsword, Recl. Trav. Chim. Pays-Bas 1947, 67, 927.
5. Heating to higher temperatures leads to unwanted oxazoline formation, see: R. M. Rodehorst, T. H. Koch, J. Am. Chem. Soc. 1975, 97, 7298.
6. a) A. K. Bhattacharya, G. Thyagarajan, Chem. Rev. 1981, 81, 415;
7. b) B. A. Arbuzov, Pure App. Chem. 1964, 9, 307.
8. 2 afforded high reactivity, but the E/Z selectivity was much lower than that obtained with DBU. For an early example of the use of DBU in highly E-selective HWE reactions, see: U. Schmidt, H. Griesser, V. Leitenberger, A. Lieberknecht, R. Mangold, R. Meyer, B. Riedl, Synthesis 1992, 487.
9. F. G. Bordwell, Acc. Chem. Res. 1988, 21, 456.
10. Benzyloxyacetaldehyde (entry 2) showed a 95:5 E:Z selectivity.
11. Thus far, the only substrates we have identified to be incompatible with this protocol are tautomerizable electron-rich aromatic aldehydes (e.g., 4-hydroxybenzaldehyde or pyrrole-2-carboxaldehyde) or aliphatic aldehydes susceptible to β-elimination under basic conditions (e.g., 3-silyloxypropionaldehyde).