ORGANIC
LETTERS
2008
Vol. 10, No. 22
5261-5263
Ring Opening of Methylenecycloalkenes
via the C-C Bond Cleavage
David Necˇas† and Martin Kotora*,†,‡
Department of Organic and Nuclear Chemistry, and Center for Structural and
Synthetic Application of Transition Metal Complexes, Faculty of Science, Charles
UniVersity, HlaVoVa 8, 128 43 Praha, Czech Republic, and Institute of Organic
Chemistry and Biochemistry, Academy of Sciences of the Czech Republic,
FlemingoVo n. 2, 166 10 Praha 6, Czech Republic
Received August 27, 2008
ABSTRACT
3-Methylenecycloalkene-1,1-dicarboxylates underwent facile ring opening via the cleavage of the unactivated C-C bond to yield aliphatic
alkenes. The reaction (intramolecular deallylation) was catalyzed by “Ni-H” species generated in situ from a NiX2(phosphine)n/R3Al mixture
and proceeded under ambient conditions. In addition, the skeletal rearrangement of a diene could be carried out by a one-pot cycloisomerization/
deallylation sequence.
A transition metal complex catalyzed carbon-carbon bond
cleavage under mild reaction conditions has been a long
pursued process of considerable theoretical and practical
interest. Generally, it can be facilitated by the presence of
an activating group and driven by a decrease of steric strain.1
Nevertheless, the ultimate goal in this area is to achieve the
cleavage of unstrained and unactivated carbon-carbon bonds
under mild reaction conditions.2 We have recently reported
the C-C bond cleavage in allylmalonates and related
compounds under a transition metal complex catalysis in the
presence of alkylaluminums. It resulted in the clean and
selective removal of the allyl moiety (deallylation).3,4
Although this process was catalyzed by a number of
transition-metal complexes (Fe, Ru, Co, Rh, Ni, and Pd),
the highest catalytic activity and generality with respect to
the substitution pattern of the allylic moiety was achieved
with simple NiX2(PPh3)2 complexes.3b,c Since it was shown
that the prenyl group (sterically hindered double bond) could
also be cleaved,3b we wanted to explore a possibility of the
cleavage of an unstrained ring system possessing a R(Cd
O)-C-C-CdC moiety, e.g., methylenecycloalkanes (Scheme
1). If the reaction could proceed, then the net result would
be a skeletal rearrangement accompanied by the double-bond
shift.5
† Charles University.
‡ Academy of Sciences of the Czech Republic.
(1) (a) Bishop, K. C., III. Chem. ReV. 1976, 76, 461–486. (b) Crabtree,
R. H. Chem. ReV. 1985, 85, 245–269. (c) Jennings, P. W.; Johnson, L. L.
Chem. ReV. 1994, 94, 2241–2290. (d) Murakami, M.; Ito, Y. Top.
Organomet. Chem. 1999, 3, 97–129.
(2) For leading references, see: (a) Watson, P. L.; Roe, D. C. J. Am.
Chem. Soc. 1982, 104, 6471–6473. (b) Bunel, E.; Burger, B. J.; Bercaw,
J. E. J. Am. Chem. Soc. 1988, 110, 976–978. (c) Kesti, M. R.; Waymouth,
R. M. J. Am. Chem. Soc. 1992, 114, 3565–3567. (d) Yang, X.; Li, J.; Marks,
T. J. J. Am. Chem. Soc. 1993, 115, 3392–3393. (e) Hajela, S.; Bercaw,
J. E. Organometallics 1994, 13, 1147–1154. (f) Rossier, C.; Niccolai, G. P.;
Basset, J.-M. J. Am. Chem. Soc. 1997, 119, 12408–12409.
(3) (a) Necˇas, D.; Kotora, M.; C´ısaˇrova´, I. Eur. J. Org. Chem. 2004,
1280–1285. (b) Necˇas, D.; Tursky´, M.; Kotora, M. J. Am. Chem. Soc. 2004,
126, 10222–10223. (c) Necˇas, D.; Tursky´, M.; Tisˇlerova´, I.; Kotora, M.
New J. Chem. 2006, 30, 671–674. (d) Tursky´, M.; Necˇas, D.; Drabina, P.;
Sedla´k, M.; Kotora, M. Organometallics 2006, 25, 901–907. (e) Necˇas,
D.; D.; Drabina, P.; Sedla´k, M.; Kotora, M. Tetrahedron Lett. 2007, 48,
4539–4541.
(5) For pioneering work on the nickel/organoaluminum-promoted
skeletal rearrangement, see: (a) Miller, R. G. J. Am. Chem. Soc. 1967, 89,
2785–2787. (b) Miller, R. G.; Pinke, P. A.; Baker, D. J. J. Am. Chem. Soc.
1970, 92, 4490–4492. (c) Gosser, L. W.; Parshall, G. W. Tetrahedron Lett.
1971, 2555–2558. (d) Miller, R. G.; Golden, H. J.; Baker, D. J.; Stauffer,
R. D. J. Am. Chem. Soc. 1971, 93, 6308–6304. (e) Miller, R. G.; Pinke,
P. A.; Stauffer, R. D.; Golden, H. J.; Baker, D. J. J. Am. Chem. Soc. 1974,
96, 4211–4220.
(4) For Ti-mediated deallylation, see: Yamazaki, T.; Kasatkin, A.;
Kawanaka, Y.; Sato, F. J. Org. Chem. 1996, 61, 2266–2267.
10.1021/ol801728f CCC: $40.75
Published on Web 10/24/2008
2008 American Chemical Society