2-alkoxy-3-methylenetetrahydrofurans by addition of 2-(bromozincmethyl)-3,3-dialkoxy-1-propenes to aldehydes and ketones followed by Pd(0)-catalyzed cyclization
J. van der Louw
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorJ. L. van der Baan
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorP. Timmerman
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorF. J. J. de Kanter
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorF. Bickelhaupt
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorG. W. Klumpp
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorJ. van der Louw
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorJ. L. van der Baan
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorP. Timmerman
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorF. J. J. de Kanter
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorF. Bickelhaupt
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorG. W. Klumpp
Scheikundig Laboratorium, Vrije Universiteit De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Search for more papers by this authorAbstract
Reaction of 2-(bromozincmethyl)-3,3-dialkoxy-1-propenes 2 with aldehydes and ketones afforded addition products 4 which underwent Pd(0)-catalyzed cyclization to 2-alkoxy-3-methylenetetrahydrofurans 5.
References and Notes
- 1a J. van der Louw, J. L. van der Baan, F. Bickelhaupt and G. W. Klumpp, Tetrahedron Lett. 28, 2889 (1987). b J. van der Louw, J. L. van der Baan, H. Stieltjes, F. Bickelhaupt and G. W. Klumpp, Tetrahedron Lett. 28, 5929 (1987). c J. van der Louw, J. L. van der Baan, H. Stichter, G. J. J. Out, F. Bickelhaupt and G. W. Klumpp, Tetrahedron Lett. 29, 3579 (1988). d J. van der Louw, C. M. D. Komen, A. Knol, F. J. J. de Kanter, J. L. van der Baan, F. Bickelhaupt and G. W. Klumpp, Tetrahedron Lett. 30, 4453 (1989).
- 2 J. van der Louw, G. J. J. Out, J. L. van der Baan, F. J. J. de Kanter, F. Bickelhaupt and G. W. Klumpp, Tetrahedron Lett. 30, 4863 (1989).
- 3 Cf. B. M. Trost, T. N. Nanninga and T. Satoh, J. Am. Chem. Soc. 107, 721 (1985). T. V. Lee, K. A. Richardson and D. A. Taylor, Tetrahedron Lett. 27, 5021 (1986). T. V. Lee, R. J. Boucher and C. J. M. Rockell, Tetrahedron Lett. 29, 689 (1988). T. V. Lee, R. J. Boucher, J. R. Porter and D. A. Taylor, Tetrahedron 44, 4233 (1988).
- 4 J. C. Depezay and Y. le Merrer, Bull. Soc. Chim. Fr. 1981, part II, 306 [n-BuLi, n-hexane, THF, - 70°C, 2 h].
- 5 1. Formaldehyde (2.5 equiv.), -70°C, 4 h; 2. -70°C← RT, 1 h; 3. Aqueous NaHCO3, ether, brine, Na2SO4; RCH3: 39%, R = C2H5: 76%, based on starting bromide.
- 6 E. W. Collington and A. I. Meyers, J. Org. Chem. 36, 3044 (1971). [1. MesCl (1.1 equiv.), LiCl (1.1 equiv.), s-collidine (1.1 equiv.), DMF, 0°C, 1 h; 2. RT, 2 h; 3. Ice-water, ether/pentane 1:1 (important: pH of the aqueous phase must be 3–4), H2O, brine, Na2SO4; RCH3: 62%, R = C2H5: 70%].
- 7 Mg powder (7 equiv., Aldrich, 50 mesh, 99+ %), 1,2-dibromoethane (0.25 equiv.), THF (4 ml/mmol chloride), 0°C, 5 h.
- 8 R = CH3: 76%, RC2H5: 74%, based on chloride precursor.
- 9 When Grignard reagents (2, MgCl instead of ZnBr) were used, yields in the addition step were lower and cyclization to give 5 was slower.
- 10 Under the conditions of the addition step, part of 4 cyclized spontaneously. However, this process stalled before complete conversion was achieved.
- 11 T. F. Tam and B. Fraser-Reid, J. Chem. Soc., Chem. Commun. 1980, 556. O. Moriya, M. Okawara and Y. Ueno, Chem. Lett. 1984, 1437. J. P. Dulcere, M. N. Mihoubi and J. Rodriguez, J. Chem. Soc., Chem. Commun. 1988, 237.
