Unusual conformational effects on the regioselectivity of olefin insertion in the rhodium-catalyzed hydroformylation of 4-methylene-1,3- dioxanes

Tetrahedron Letters

Volumn 39, Issue 36, 1998, Pages 6423-6426

  Sarraf, Stella T ^a   Leighton, James L ^a  

^a Och Spine at New York Presbyterian Hospitals   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

4 METHYLENE 1,3 DIOXANE DERIVATIVE; ALKENE; DIOXANE DERIVATIVE; RHODIUM; UNCLASSIFIED DRUG;

ARTICLE; CATALYSIS; DRUG CONFORMATION; REACTION ANALYSIS;

EID: 0032171519     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)01351-3     Document Type: Article

References (15)

1. 1. Leighton, J. L.; O'Neil, D. N. J. Am. Chem. Soc. 1997, 119, 11118-11119.
2. 2. Rychnovsky has recently developed a highly effective approach to acetal protected anti-1,3-diols. See: Powell, N. A.; Rychnovsky, S. D. Tetrahedron Lett. 1998, 39, 3103-3106, and references therein.
3. 3. This prediction and all mechanistic results presented herein are based on the presumption of irreversible/rate-determining olefin insertion, for which we have provided evidence. See ref. 1.
4. 4. Seebach has reported the preparation of this dioxinone in 29% yield: Kinkel, J. N.; Gysel, U.; Blaser, D.; Seebach, D. Helv. Chim. Acta 1991, 74, 1622-1635. We have improved the yield of this process to 73% by using a high pressure apparatus.
5. 5. Seebach, D.; Zimmerman, J.; Gysel, U.; Ziegler, R.; Ha, T.-K. J. Am. Chem. Soc. 1988, 110, 4763-4772.
6. 6. Petasis, N. A.; Lu, S.-P. Tetrahedron Lett. 1996, 37, 141-144.
7. 13C NMR, IR, and HRMS). Stereochemical assignments were based on selective ID NOESY experiments.
8. 8. The conformations of some 1,3-dioxanes have been studied in detail. See: (a) Pihlaja, K.; Kivimäki, M.; Myllyniemi, A.-M.; Nurmi, T. J. Org. Chem. 1982, 47, 4688-4692.
9. (b) Rychnovsky, S. D.; Yang, G.; Powers, J. P. J. Org. Chem. 1993, 58, 5251-5255, and references therein.
10. 9. That the 1,4-twist-boat conformation is at least accessible if not the dominant form for 5 is indicated by the observation of a nOe between the cis protons at the 2 and 5 positions.
11. 10. Substrate 8 was prepared in direct analogy to substrate 5 (Scheme 2). Diastereoselective cuprate additions to pinacolone-derived dioxinones have precedent: Organ, M. G.; Froese, R. D. J.; Goddard, J. D.; Taylor, N. J.; Lange, G. L. J. Am. Chem. Soc. 1994, 116, 3312-3323.
12. 11. For an excellent review of Curtin-Hammett kinetics, see: Seeman, J. I. Chem.Rev. 1983, 83, 83-134.
13. 12. Substrate 9 was prepared in direct analogy to substrate 5 (Scheme 2) using BuLi in the first step.
14. 5
15. 14. A subtle point which remains to be elucidated is why the tertiary rhodium-alkyls derived from substrates 1 proceed to give aldehyde products while the tertiary rhodium-alkyls derived from substrates 5 and 9 undergo β-hydride elimination. In this context it is interesting to note that the dihedral angle between the Rh and the cis β-hydrogen in the 1,4-twist-boat conformation predicted for the latter should be ∼30° while that for the chair form predicted for the former should be ∼60°.