C O M M U N I C A T I O N S
Table 2. Asymmetric Hydrovinylation of 1,3-dienes (eq 3)a
formed with exquisite regioselectivity (1,2-addtion at the less
hindered olefin). The racemic chiral olefin 3 gave a nearly ∼2:1
mixture of diastereomers. The results of hydrovinylation of other
typical dienes are shown in Table 1.13 In general, excellent yields
(>97%) and selectivities (>95%) are observed for the hydroviny-
lation of both cyclic and acyclic dienes (entries 1, 2, 5-9) under 1
atm of ethylene. Lack of selectivity is seen only for 1-vinylcyclo-
hexene (7, entry 3) and the 1-vinylcyclopentene 9 (entry 4, prepared
by enyne metathesis), which gave a mixture of 1,2- and 1,4- addition
products.
a See eq 3 for typical procedure and Supporting Information for
experimental details.
The most promising results with model compounds, suitable for
a study of the exocyclic stereochemistry problem, are shown in eq
3 and Table 2. Hydrovinylation of 11, 13, and 15, under our
Acknowledgment. This paper is dedicated to Professor David
Hart to honor his numerous scientific contributions and outstanding
service to chemical education. Financial assistance for this research
by U.S. National Science Foundation (CHE-0308378) and the ACS-
PRF (36617-AC1) is gratefully acknowledged.
Supporting Information Available: Full experimental details of
various hydrovinylation reactions, spectroscopic and chromatographic
data for characterization of compounds. This material is available free
standard conditions (eq 3) using the phospholane (L1)7e or the
phosphoramidite ligand (L2) gave exceptionally high yields and
regio- and enantioselectivities for these cyclic dienes.13 Acyclic
diene 17 under these conditions gave nearly racemic product.
The absolute configuration of the 14 was established by its
conversion to the fully aromatic product of known14 configuration
(eq 4a). The configurations of 12 and 16 were assigned by analogy.
References
(1) Bogdanovic´, B.; Henc, B.; Meister, B.; Pauling, H.; Wilke, G. Angew.
Chem., Int. Ed. 1972, 11, 1023.
(2) For recent reviews of hydrovinylation reaction, see: (a) RajanBabu, T.
V. Chem. ReV. 2003, 103, 2845. (b) Jolly, P. W.; Wilke, G. Hydroviny-
lation. In Applied Homogeneous Catalysis with Organometallic Com-
pounds; Cornils, B., Herrmann, W. A., Eds.; VCH: New York, 1996;
Vol. 2, p 1024.
(3) Wilke, G.; Monkiewicz, J.; Kuhn, H. U.S. Patent, 4,912,274, 1990; Chem.
Abstr. 1991, 114, 43172.
(4) Buono, G.; Siv, C.; Peiffer, G.; Triantaphylides, C.; Denis, P.; Mortreux,
A.; Petit, F. J. Org. Chem. 1985, 50, 1781.
(5) Angermund, K.; Eckerle, A.; Lutz, F. Z. Naturforsch., B: Chem. Sci. 1995,
50, 488.
(6) He, Z.; Yi, C. S.; Donaldson, W. A. Org. Lett. 2003, 5, 1567.
(7) (a) Nomura, N.; Jin, J.; Park, H.; RajanBabu, T. V. J. Am. Chem. Soc.
1998, 120, 459. (b) RajanBabu, T. V.; Nomura, N.; Jin, J.; Nandi, M.;
Park, H.; Sun, X. J. Org. Chem. 2003, 68, 8431. (c) Nandi, M.; Jin, N.;
RajanBabu, T. V. J. Am. Chem. Soc. 1999, 121, 9899. (d) Park, H.;
RajanBabu, T. V. J. Am. Chem. Soc. 2002, 124, 734. (e) Zhang, A.;
RajanBabu, T. V. Org. Lett. 2004, 6, 1515.
(8) Francio`, G.; Faraone, F.; Leitner, W. J. Am. Chem. Soc. 2002, 124, 736.
(9) Arnold, L. A.; Imbos, R.; Mandoli, A.; de Vries, A. H. M.; Naasz, R.;
Feringa, B. L. Tetrahedron 2000, 56, 2865.
(10) (a) Kumareswaran, R.; Nandi, M.; RajanBabu, T. V. Org. Lett. 2003, 5,
4345. (b) Park, H.; Kumareswaran, R.; RajanBabu, T. V. Tetrahedron
2005, 61, 6352.
(11) For a leading reference, discussion, and citations of earlier work, see:
Guevel, A.-C.; Hart, D. J. J. Org. Chem. 1996, 61, 465 and references
therein.
(12) For recent references: (a) Rodr´ıguez, I. I.; Rodr´ıguez, A. D. J. Nat. Prod.
2003, 66, 855 and references therein. (b) Tanaka, J.-i.; Ogawa, N.; Liang,
J.; Higa, T. Tetrahedron 1993, 49, 811. Synthetic studies: erogorgiaene:
(c) Cesati, R. R., III; de Armas, J.; Hoveyda, A. H. J. Am. Chem. Soc.
2004, 126, 96. Pseudopteroxazole: (d) Davidson, J. P.; Corey, E. J. J.
Am. Chem. Soc. 2003, 125, 13486.
The sense of asymmetric induction is consistent with the model
we proposed for asymmetric hydrovinylation of vinylarenes.7e The
ee’s were unambiguously established by GC, HPLC, and/or Mosher
ester13 methods.
A number of different strategies including hydroboration and
directed hydrogenation can be envisioned for controlling the
configuration of the ring carbon to which the side chain is attached.
One example is shown in eq 4b. The hydroboration (9-BBN, H2O2)
of 14 followed by directed hydrogenation using Crabtree’s catalyst,
([(COD)(Cy3P)Ir(py)]+PF6-), gives a reduced product (21, dr 30:
1) with very high stereoselectivity.13
(13) See Supporting Information for full experimental details, analytical data,
characterization, and assignments of configurations of 14, 21, and 22.
(14) Menicagli, R.; Piccolo, O.; Lardicci, L.; Wis, M. L. Tetrahedron 1979,
35, 1301.
Further expansion of the scope of the asymmetric reaction and
its applications for the synthesis of natural products will be reported
in due course.
JA0561338
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