ORGANIC
LETTERS
1999
Vol. 1, No. 3
485-486
Carbometalations of Simple Alkenes
with Allyldibromoborane
Doug E. Frantz and Daniel A. Singleton*
Department of Chemistry, Texas A&M UniVersity, College Station, Texas 77843
Received May 17, 1999
ABSTRACT
The allylboration of alkenes with allyldibromoborane is described. Utilizing an improved methodology for the synthesis of allyldibromoborane,
1,3-dienes, styrene, and even isolated alkenes could be carbometalated in high yield regio- and stereospecifically at 0 °C. This high reactivity
of allyldibromoborane significantly expands the scope of carbometalations of alkenes.
The development of methodology for the carbometalation
of simple alkenes has been a challenging goal for organic
chemists. While general methodologies have been developed
for the carbometalation of electron-deficient alkenes (e.g.,
cuprate chemistry) and isolated alkynes, carbometalations of
unactivated alkenes and dienes have been more limited.
Useful examples include polymerizations, intramolecular
cyclizations,1 additions to allylic alcohols or amines,2 and
uncatalyzed3 and catalyzed4 additions to terminal and highly
strained alkenes.5 Carbometalations with allylic reagents,
describable as metallo-ene reactions, have often been more
successful. This includes the addition of Grignards and zincs
to monosubstituted and strained alkenes,6 intramolecular
examples,7 and the carbometalations of alkynes and special-
ized alkenes with allylboranes.8
We recently reported on the utility of allylborations with
allyldichloroborane.9 These highly electrophilic reagents
rapidly carbometalate allylic silanes and vinyl ethers in high
yields. A substantial limitation was that allyldichloroborane
was not sufficiently reactive with simple 1,3-dienes, styrenes,
and isolated alkenes. At the time we noted that allyldibro-
moborane (1) appeared to be much more reactive and we
described in a single example its reaction with 1,3-cyclo-
hexadiene to form an addition product in moderate yield.
Unfortunately, our in situ synthesis of 1 was not clean, and
the apparent destruction of alkenes by byproducts formed
in the process hampered the exploration of 1’s carbometa-
lation chemistry.
Taking advantage of an improved synthesis of 1, we report
here on its allylboration reactions. It is found that 1
carbometalates simple alkenes and dienes regio- and ste-
reospecifically in high yield.
The NMR observation of 1 from the reaction of BBr3 with
allyltrialkylstannanes had been previously reported,10 and we
have reported the analogous reaction with allyltrimethyl-
(1) Barluenga, J.; Sanz, R.; Granados, A.; Fan˜ana´s, F. J. J. Am. Chem.
Soc. 1998, 120, 4865. Shaughnessy, K. H.; Waymouth, R. M. J. Am. Chem.
Soc. 1995, 117, 5873. Negishi, E.; Jensen, M. D.; Kondakov, D. Y.; Wang,
S. J. Am. Chem. Soc. 1994, 116, 8404. Zhang, Y.; Negishi, E. J. Am. Chem.
Soc. 1989, 111, 3454.
(2) Richey, H. G., Jr.; Erickson, W. F.; Heyn, A. S. Tetrahedron Lett.
1971, 48, 2183. Eisch, J. J.; Merkley, J. H.; Galle, J. E. J. Am. Chem. Soc.
1979, 101, 1148. See also: Hoveyda, A. H.; Xu, Z.; Morken, J. P.; Houri,
A. F. J. Am. Chem. Soc. 1991, 113, 8950.
(3) Lehmkuhl, H. Bull. Chim. Soc. Fr. II 1981, 87.
(4) Dzhemilev, U. M.; Vostrikova, O. S. J. Organomet. Chem. 1985,
285, 43. Hoveyda, A. H.; Xu, Z. J. Am. Chem. Soc. 1991, 113, 5079.
Takahashi, T.; Seki, T.; Nitto, Y.; Saburi, M.; Rousset, C. J.; Negishi, E. J.
Am. Chem. Soc. 1991, 113, 6266.
(5) Nakamura, E.; Nakamura, M.; Miyachi, Y.; Koga, N.; Morokuma,
K. J. Am. Chem. Soc. 1993, 115, 99.
(7) Oppolzer, W. Angew. Chem., Int. Ed. Engl. 1989, 28, 38.
(8) For reviews, see: Mikhailov, B. M. Russ. Chem. ReV. 1976, 45, 557.
Bubnov, Y. N. Pure Appl. Chem. 1987, 59, 895.
(6) Lehmkuhl, H. In Organometallics in Organic Synthesis; De Meijere,
A., Dieck, T., Eds.; Springer-Verlag: New York, 1987; pp 185-202.
Nakamura, M.; Arai, M. Nakamura, E. J. Am. Chem. Soc. 1995, 117, 1179.
Yamamoto, Y.; Asao, N. Chem. ReV. 1993, 93, 2207.
(9) Singleton, D. A.; Waller, S. C.; Zhang, Z.; Frantz, D. E.; Leung,
S.-W. J. Am. Chem. Soc. 1996, 118, 9986-9987.
(10) Harston, P.; Wardell, J. L.; Marton, D.; Tagliavini, G.; Smith, P. J.
Inorg. Chim. Acta 1989, 162, 245.
10.1021/ol990673q CCC: $18.00 © 1999 American Chemical Society
Published on Web 06/23/1999