One-pot enol silane formation-Mukaiyama aldol-type addition to dimethyl acetals mediated by TMSOTf

Journal of Organic Chemistry

Volumn 73, Issue 8, 2008, Pages 3299-3302

  Downey, C Wade ^a   Johnson, Miles W ^a   Tracy, Kathryn J ^a  

^a UNIVERSITY OF RICHMOND   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AMIDES; ESTERS; KETONES; PURIFICATION;

DIMETHYL ACETALS; ENOL SILANE FORMATION;

SILANES;

ACETAL DERIVATIVE; ALDEHYDE DERIVATIVE; AMIDE; AMINE; ESTER DERIVATIVE; KETONE DERIVATIVE; POLYCYCLIC AROMATIC HYDROCARBON DERIVATIVE; SILANE; THIOESTER; TRIFLUOROMETHANESULFONIC ACID;

ALKYLATION; ARTICLE; ELIMINATION REACTION; MUKAIYAMA REACTION; ONE POT SYNTHESIS; QUANTUM YIELD; REACTION ANALYSIS;

ACETALS; ACETOPHENONES; ALDEHYDES; BENZALDEHYDES; MAGNETIC RESONANCE SPECTROSCOPY; MESYLATES; MOLECULAR STRUCTURE; SILANES; TRIMETHYLSILYL COMPOUNDS;

EID: 42149172683     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo8001084     Document Type: Article

References (21)

1. (a) Mukaiyama, T.; Banno, K.; Narasaka, K. J. Am. Chem. Soc. 1974, 96, 7503-7509.
2. For a review, see: (b) Carreira, E. M. In Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A., Yamamoto, H., Eds.; Springer-Verlag: Berlin, Germany, 1999; Vol. 3, pp 997-1065.
3. For more recent examples, see: (c) Rech, J. C.; Floreancig, P. E. Org. Lett. 2005, 7, 5175-5178.
4. (d) Jung, M. E.; Zhang, T.-H. Org. Lett. 2008, 10, 137-140.
5. (a) Downey, C. W.; Johnson, M. W. Tetrahedron Lett. 2007, 48, 3559-3562.
6. For intramolecular precedents for this reaction, see: (b) Hoye, T. R.; Dvornikovs, V.; Sizova, E. Org. Lett. 2006, 8, 5191-5194.
7. (c) Rassu, G.; Auzzas, L.; Pinna, L.; Zombrano, V.; Battistini, L.; Zanardi, F.; Marzocchi, L.; Acquotti, D.; Casiraghi, G. J. Org. Chem. 2001, 66, 8070-8075.
8. For the use of silyl trifluoromethanesulfonates as Lewis acids in Mukaiyama-type addition to acetals, see: (a) Murata, S.; Suzuki, M.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 3248-3249.
9. (b) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron 1988, 44, 4259-4275.
10. For a strategy similar to the one reported here, but with a boron Lewis acid, see: (c) Li, L.-S.; Das, S.; Sinha, S. C. Org. Lett. 2004, 6, 127-130.
11. Similar conditions (TESOTf/2,6-lutidine) have been used to convert symmetric acetals to mixed acetals via a similar oxocarbenium intermediate. See: Fujioka, H.; Okitsu, T.; Sawama, Y.; Murata, N.; Li, R.; Kita, Y. J. Am. Chem. Soc. 2006, 128, 5930-5938.
12. Synthesis of the dimethyl acetal derived from p-nitrobenzaldehyde proved nontrivial, preventing its inclusion in this study.
13. Styrenyl bonds are easily cleaved by ozonolysis to yield an aldehyde. For example, see: Evans, D. A.; Bender, S. L.; Morris, J. J. Am. Chem. Soc. 1988, 110, 2506-2526.
14. Ketals were generally converted to enol ethers under the reaction conditions.
15. β-Methoxy carbonyl compounds are known to undergo elimination under Lewis acidic conditions. See: Ramirez, F.; Rubin, M. B. J. Am. Chem. Soc. 1955, 77, 2905-2907.
16. For an example of a thioester aldol adduct used as a building block in the asymmetric total synthesis of pectenotoxin, see: Evans, D. A.; Rajapakse, H. A.; Chiu, A.; Stenkamp, D. Angew. Chem., Int. Ed. 2002, 41, 4573-4576.
17. For the direct conversion of thioesters to aldehydes by Fukuyama reduction, see: Fukuyama, T.; Lin, S.-L.; Li, L. J. Am. Chem. Soc. 1990, 112, 7050-7051.
18. 1H NMR suggests that enolization of ester and amide substrates is slow under the reaction conditions, typically less than 10% after 15 min at ambient temperature. In contrast, conversion of aromatic ketones to enol silanes under identical conditions is >90% complete after 15 min.
19. 1H NMR spectrum. No yield was determined. Methoxymethyl protection of amides is known to occur under similar conditions. For example, see: Szmigielski, R.; Danikiewicz, W. Synlett 2003, 372-376.
20. Assignment of relative stereochemistry for product 26 is based on literature precedent (ref 3b). Assignment for product 27 is by analogy.
21. For a literature synthesis of product 1, see: Torii, S.; Inokuchi, T.; Takagishi, S.; Horike, H.; Kuroda, H.; Uneyama, K. Bull. Chem. Soc. Jpn. 1987, 60, 2173-2188.