The direct synthesis of 2-Oxazolines from carboxylic esters using lanthanide chloride as catalyst

Tetrahedron Letters

Volumn 38, Issue 40, 1997, Pages 7019-7020

  Zhou, Peiwen ^a   Blubaum, Jason E ^a   Burns, Christopher T ^a   Natale, Nicholas R ^a  

^a UNIVERSITY OF IDAHO   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

OXAZOLINE DERIVATIVE;

ARTICLE; DRUG SYNTHESIS; IN VITRO STUDY; METHODOLOGY; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0030770085     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)01641-9     Document Type: Article

References (13)

1. a) Imamoto, T. Lanthanides in Organic Synthesis, Academic Press, 1994.
2. b) Kobayashi, S. Synlett, 1994, 689.
3. c) Molander, G. A. Chem. Rev. 1992, 92, 29
4. For recently review: Grant, T. G.; Meyers, A. I. Tetrahedron, 1994, 50, 2997.
5. Natale, N. R.; Mirzaei, Y. R.; Org. Prep. Proced. Int. 1993, 25, 515.
6. Green, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis; Second edition; John Wiley & Sons Inc., New York, 1991, pp. 265-266, 433-436.
7. a) Pique, C.; Fahndrich, B.; Pfaltz, A. Synlett, 1995, 491.
8. b) Evans, D. A.; Miller, S. J.; Lectka, T. J. Am. Chem. Soc. 1993, 115, 6460.
9. c) Corey, E. J. and Ishihara, K.; Tetrahedron Lett. 1992, 33, 6807.
10. Natale, N. R.; McKenna, J. I.; Niou, C-S.; Borth, M.; Hope, H. J. Org. Chem. 1985, 50, 5660.
11. Vorbruggen H.; Krolikiewicz, K. Tetrahedron 1993, 49, 9353.
12. Typical experimental procedure: To a flask charged with anhydrous lanthanum chloride (0.2 mmol) was added 20 ml dry toluene and 2-amino-2-methyl-1-propanol (5 mmol), then nBuLi (1.99 M in pentane, 4.4 mmol) was added to this suspension at 0°C. After the reaction was stirred at 0°C for 15 minutes, the flask was warmed to reflux (100°C). Carboxylic ester (2 mmol) was added and the reaction mixture was refluxed for an additional 12 hours. The suspension was cooled to room temperature, after filteration and washing with chloroform (3 × 15mL), extractive isolation gave the desired product in very pure form. Further purification can be carried out with kugelrohr distillation or flash chromatography (silica gel; EtOAc: Hexane).
13. The rotation data for Entry 8: Ahn, K. H.; Cho, C.-W.; Baek, H.-H.; Park, J.; Lee, S., J. Org. Chem. 1996, 61, 4937.