8682 J. Am. Chem. Soc., Vol. 120, No. 34, 1998
Pezacki et al.
near the diffusion controlled limit; kpyr ) (1-8) × 109 M-1
s-1. Dialkylcarbenes tend to show electrophilic singlet state
chemistry,3,4 and intramolecular 1,2-hydrogen shifts are usually
dominant for these intermediates. Exceptions include carbenes
without R-hydrogens as exemplified by di(1-adamantylcar-
bene).13 In singlet alkyl and dialkylcarbenes those shifts involve
transition states in which the migrating atom is hydride-like.3,4
The electrophilic character of such carbenes3,4 is also indicated
by their preference for electron-rich olefins in cyclopropanation
reactions and by their rapid reactions with substrates containing
heteroatoms, such as pyridine.3,4d-f The rapid (close to the
diffusion-controlled limit) formation of pyridine ylide intermedi-
ates from singlet dialkylcarbenes suggests that reactions of these
carbenes with heteroatom donors could successfully compete
with intramolecular rearrangement reactions.
abstraction from CO2,14 N-oxides,15 PF3O,16 epoxides,17 aziri-
dines,18 thiiranes,19 and carbonyl compounds.20 Shields and
Schuster have shown that oxygen atom abstraction from
epoxides by singlet fluorenylidene (FL) occurs stereospecifically
(eq 2).17a
(2)
Reaction of carboethoxycarbene with styrene oxide leads to
deoxygenation products as well as a diastereomeric mixture of
oxetanes,17c presumably resulting from the intramolecular rear-
rangement of an oxonium ylide intermediate. Carboethoxycar-
bene has also been shown to abstract the sulfur atom from
cyclohexene sulfide without similar intramolecular rearrange-
ment.19
Herein we report heteroatom transfer reactions from oxiranes
and thiiranes to a variety of carbenes of different structure and
philicity (mCXY). We have explored the heteroatom transfer
chemistry of benzylchlorocarbene (2a),21-24 phenylchlorocar-
bene (2b),10 and methoxyphenylcarbene (2c),9b all of which have
singlet ground states and are ambiphilic. These carbenes were
generated from the photolysis of the corresponding diazirine
precursors (1a-c). Oxadiazoline precursors were used to study
heteroatom transfer reactions of dimethylcarbene (8a), cyclobu-
Electrophilic singlet carbenes are capable of abstracting
oxygen and sulfur atoms by mechanisms involving the formation
of ylide intermediates (or ylide-like transition states), followed
by heteroatom transfer. Some examples include heteroatom
(4) For some examples, see: (a) Jackson, J. E.; Soundararajan, N.; Platz,
M. S.; Doyle, M. P.; Liu, M. T. H.; Tetrahedron Lett. 1989, 30, 1335. (b)
Jackson, J. E.; Soundararajan, N.; Platz, M. S.; Liu, M. T. H. J. Am. Chem.
Soc. 1988, 110, 5595. (c) Platz, M. S.; Modarelli, D. A.; Morgan, S.; White,
W. R.; Mullins, M.; Celebi, S.; Toscano, J. P. Progress in Reaction Kinetics;
Rodgers, M. A., Ed.; Elsevier: Oxford, 1994; Vol. 19, p 93. (d) Modarelli,
D. A.; Platz, M. S. J. Am. Chem. Soc. 1991, 113, 8985. (e) Morgan, S.;
Jackson, J. E.; Platz, M. S. J. Am. Chem. Soc. 1991, 113, 2782. (f) Modarelli,
D. A.; Morgan, S.; Platz, M. S. J. Am. Chem. Soc. 1992, 114, 7034. (g)
Liu, M. T. H.; Bonneau, R. J. Am. Chem. Soc. 1990, 112, 3915. (h) Bonneau,
R.; Liu, M. T. H.; Suresh, R. V. J. Phys. Chem. 1989, 93, 4802. (i) Liu, M.
T. H.; Bonneau, R. J. Am. Chem. Soc. 1992, 114, 3604. (j) Liu, M. T. H.;
Bonneau, R. J. Am. Chem. Soc. 1989, 111, 6873. (k) Doyle, M. P.; Taunton,
J.; Oon, S.-M.; Liu, M. T. H.; Soundararajan, N.; Platz, M. S.; Jackson, J.
E. Tetrahedron Lett. 1988, 29, 5863. (l) Moss, R. A.; Ho, G.-J. J. Am.
Chem. Soc. 1990, 112, 5642. (m) Moss, R. A.; Zdrojewski, T.; Ho, G.-J. J.
Chem. Soc., Chem. Commun. 1991, 946. (n) Moss, R. A.; Liu, W.
Tetrahedron Lett. 1996, 37, 279. (o) Moss, R. A.; Liu, W. J. Chem. Soc.,
Chem. Commun. 1993, 1597. (p) Chidester, W.; Modarelli, D. A.; White,
W. R., III.; Whitt, D. E.; Platz, M. S. J. Phys. Org. Chem. 1994, 7, 24. (q)
Jackson, J. E.; Soundararajan, N.; White, W.; Liu, M. T. H.; Bonneau, R.;
Platz, M. S. J. Am. Chem. Soc. 1989, 111, 6874. (r) Perrin, H. M.; White,
W. R., III.; Platz, M. S. Tetrahedron Lett. 1991, 32, 4443. (s) Modarelli,
D. A.; Platz, M. S. J. Am. Chem. Soc. 1993, 115, 470. (t) Jones, M. B.;
Platz, M. S. Tetrahedron Lett. 1990, 31, 953. (u) Modarelli, D. A.; Platz,
M. S. J. Am. Chem. Soc. 1993, 115, 10440. (v) Toscano, J. P.; Platz, M. S.;
Nikolaev, V.; Cao, Y.; Zimmt, M. B. J. Am. Chem. Soc. 1996, 118, 3527.
(w) White, W. R., III.; Platz, M. S. J. Org. Chem. 1992, 57, 2841. (x)
Ford, F.; Yuzawa, T.; Platz, M. S.; Matzinger, S.; Fu¨lscher, M. J. Am. Chem.
Soc. 1998, 120, 4430.
(14) For oxygen atom abstractions from CO2, see: (a) Chateauneuf, E.
J. Res. Chem. Intermed. 1994, 20, 159. (b) Wierlacher, S.; Sauer, W. W.;
Liu, M. T. H. J. Org. Chem. 1992, 57, 1051. (c) Sander, W. W. J. Mol.
Struct. 1990, 222, 21. (d) Koch, M.; Temp, F.; Wagner, R.; Wagner, H.
Gg. Ber. Bunsen-Ges. Phys. Chem. 1990, 94, 645. (e) Sander, W. W. J.
Org. Chem. 1989, 54, 4265. (f) Laufer, A. H.; Bass, A. M. Chem. Phys.
Lett. 1977, 46, 151. (g) Hsu, D. S. Y.; Lin, M. C. Int. J. Chem. Kinet.
1977, 9, 1507. (h) Kistiakowsky, G. B.; Sauer, K. J. Am. Chem. Soc. 1968,
90, 1066. (i) Milligan, D. E.; Jacox, M. E. J. Chem. Phys. 1962, 36, 2911.
(15) For oxygen atom abstractions from N-oxides, see: (a) Field, K. W.;
Schuster, G. B. J. Org. Chem. 1988, 53, 4000. (b) Schweiter, E. E.; O’Neill,
G. J. J. Org. Chem. 1963, 28, 2460.
(16) For oxygen atom abstractions from PF3O, see: Mahler, W. J. Am.
Chem. Soc. 1968, 90, 523.
(17) For oxygen atom abstractions from epoxides, see: (a) Shields, C.
J.; Schuster, G. B. Tetrahedron Lett. 1987, 28, 853. (b) Wittig, G.; Schlosser,
M. Tetrahedron 1962, 18, 1026. (c) Nozaki, H.; Takaya, H.; Noyori, R.
Tetrahedron Lett. 1965, 2563. (d) Nozaki, H.; Takaya, H.; Noyori, R.
Tetrahedron 1966, 22, 3393. (e) Martin, M.; Ganem, B. Tetrahedron Lett.
1984, 251.
(18) Hata, Y.; Watanabe, M. Tetrahedron Lett. 1972, 3827, 4659.
(19) Hata, Y.; Watanabe, M.; Inoue, S.; Oae, S. J. Am. Chem. Soc. 1975,
97, 2553.
(5) Ge, C. S.; Jane, E. G.; Jefferson, E. A.; Liu, W.; Moss, R. A.;
Włostowska, J.; Xue, S. J. Chem. Soc., Chem. Commun. 1994, 1479.
(6) (a) Moss, R. A. Acc. Chem. Res. 1989, 22, 15. (b) Moss, R. A. Acc.
Chem. Res. 1980, 13, 58. (c) Moss, R. A.; Jang, E. G.; Fan, H.; Włostowski,
M.; Krogh-Jespersen, K. J. Phys. Org. Chem. 1992, 5, 104. (d) Sheridan,
R. S.; Moss, R. A.; Wilk, B. K.; Shen, S.; Włostowski, M.; Kesselmayer,
M. A.; Subramanian, R.; Kmiecik-Ławrynowicz, G.; Krogh-Jespersen, K.
J. Am. Chem. Soc. 1988, 110, 7563.
(20) For oxygen atom abstractions from carbonyl compounds, see:
Kovacs, D.; Lee, M.-S.; Olson, D.; Jackson, J. E. J. Am. Chem. Soc. 1996,
118, 8144.
(7) Bonneau, R.; Liu, M. T. H.; Lapouyade, R. J. Chem. Soc., Perkin
Trans. 1 1989, 1547.
(8) Jones, M. B.; Platz, M. S. J. Org. Chem. 1991, 56, 1694.
(21) For reviews, see: (a) Moss, R. A. Pure Appl. Chem. 1995, 67, 741.
(b) Liu, M. T. H. Acc. Chem. Res. 1994, 27, 287. (c) Nickon, A. Acc. Chem.
Res. 1993, 26, 84. (d) Schaefer, H. F., III Acc. Chem. Res. 1979, 12, 288.
(e) Kirmse, W. Carbene Chemistry, 2nd ed.: Academic Press: New York,
1971. (f) Jones, M. Jr.; Moss, R. A. Carbenes: Wiley: New York, 1973,
1975; Vol. 1 and 2.
(22) References 4g,i. (a) Jackson, J. E.; Soundararajan, N.; White, W.;
Liu, M. T. H.; Bonneau, R.; Platz, M. S. J. Am. Chem. Soc. 1989, 111,
6874. (b) Bonneau, R.; Liu, M. T. H.; Subramanian, R.; Linkletter, B.;
Stevens, I. D. R. Laser Chem. 1989, 10, 267. (c) Bonneau, R.; Liu, M. T.
H.; Kim, K. C.; Goodman, J. L. J. Am. Chem. Soc. 1996, 118, 3829. (d)
Liu, M. T. H.; Suresh, R. V.; Soundararajan, N.; Vessey, E. G. J. Chem.
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(9) (a) The reactivities of carbene intermediates may be predicted using
6a,b
the philicity scale mCXY
.
Values for mCXY are determined empirically
based on selectivities of carbenes toward olefins or they can be calculated
+
using σR and σI values (see Discussion). (b) The rate constant for the
reaction of methoxyphenylcarbene with pyridine was taken from Moss, R.
A.; Shen, S.; Hadel, L. M.; Kmiecik-Ławrynowicz, G.; Włostowska, J.;
Krogh-Jespersen J. Am. Chem. Soc. 1987, 109, 4341.
(10) (a) Jackson, J. E.; Soundararajan, N.; Platz, M. S. J. Am. Chem.
Soc. 1988, 110, 5595. (b) Gould, I. R.; Turro, N. J.; Butcher, J. J.;
Doubleday: C. J.; Hacker, N. P.; Lehr, G. F.; Moss, R. A.; Cox, D. P.;
Guo, W.; Munjal, R. C.; Perez, L. A.; Fedorynski, M. Tetrahedron 1985,
41, 1587.
(11) For some examples, see: refs 4d-f. Kirmse, W.; Meinert, T.;
Modarelli, D. A.; Platz, M. S. J. Am. Chem. Soc. 1993, 115, 8918.
(12) Robert, M.; Toscano, J. P.; Platz, M. S.; Abbot, S. C.; Kirchhoff,
M. M.; Johnson, R. P. J. Phys. Chem. 1996, 100, 18426.
(13) Myers, D. R.; Senthilnathan, V. P.; Platz, M. S.; Jones, M., Jr. J.
Am. Chem. Soc. 1986, 108, 4232.
(23) See ref 3a. (a) Liu, M. T. H.; Soundararajan, N.; Paike, N. J. Org.
Chem. 1987, 52, 4223. (b) Liu, M. T. H.; Suresh, R. V.; Soundararajan,
N.; Vessy, E. G. J. Chem. Soc., Chem. Commun. 1989, 12. (c) Liu, M. T.
H.; Chapman, R. G.; Bonneau, R. J. Photochem. Photobiol. A. Chem. 1992,
63, 115.
(24) Liu, T. H. M.; Subramanian, R. J. Org. Chem. 1985, 50, 3218.