1700
J. Ramírez, E. Fernandez
SPECIAL TOPIC
Interscience: New York, 1975. (d) Pelter, A.; Smith, K.;
Brown, H. C. In Borane Reagents; Academic Press: New
York, 1988.
ing a,a-difluoroketone. When the electrophilic fluorina-
tion was carried out in presence of traces of H2O or under
air atmosphere, the product obtained was mainly the di-
fluoromethyl alcohol (Scheme 4).
(2) (a) Cragg, G. M. L. In Organoboranes in Organic Synthesis;
Dekker: New York, 1973. (b) Onak, T. In Organoborane
Chemistry; Academic Press: New York, 1975.
(3) Marder, T. B.; Norman, N. C. Top. Catal. 1998, 5, 63.
(4) Dembitsky, V. M.; Abu Ali, H.; Srebnik, M. Appl.
Organomet. Chem. 2003, 17, 327.
(5) Ishiyama, T.; Miyaura, N. Chem. Rec. 2004, 3, 271.
(6) (a) Ishiyama, T.; Matsuda, N.; Miyaura, N.; Suzuki, A. J.
Am. Chem. Soc. 1993, 115, 11018. (b) Miyaura, N.; Suzuki,
A. Chem. Rev. 1995, 95, 2457. (c) Miyaura, N. In Advances
in Metal-Organic Chemistry; JAI: Stanford, 1998.
(d) Suzuki, A. In Metal-Catalyzed Cross-Coupling
Reactions; Wiley-VCH: Weinheim, 1998.
(7) Ishiyama, T.; Matsuda, N.; Murata, M.; Ozawa, F.; Suzuki,
A.; Miyaura, N. Organometallics 1996, 15, 713.
(8) Lesley, G.; Nguyen, P.; Taylor, N. J.; Marder, T. B.; Scott,
A. J.; Clegg, W.; Norman, N. C. Organometallics 1996, 15,
5137.
(9) Iveson, C. N.; Smith, M. R. III Organometallics 1996, 15,
5155.
(10) Baker, R. T.; Nguyen, P.; Marder, T. B.; Westcott, S. A.
Angew. Chem., Int. Ed. Engl. 1995, 34, 1336.
O
F
F
N2
air
O
O
96%
HO
O
B
B O
Selectfluor
MeCN
F
H
F
15
84%
Scheme 4
We are now working on performing the tandem sequence
diboration/fluorination in one global step. Towards this
end, we need first to optimize the catalytic reaction condi-
tions to perform the diboration under acetonitrile as the
common solvent. These results and the scope of the one-
pot reaction to other substituted internal and terminal
alkynes will be published in due course.
(11) Thomas, R. L.; Souza, F. E. S.; Marder, T. B. J. Chem. Soc.,
Dalton Trans. 2001, 1650.
(12) Mann, G.; John, K. D.; Baker, R. T. Org. Lett. 2000, 2, 2105.
(13) Ishiyama, T.; Yamamoto, M.; Miyaura, N. Chem. Lett. 1996,
1117.
Catalytic Diboration of Alkynes; Typical Procedure
Method A: To a sample of [Pt(NBE)3] (0.025 mmol) dissolved in
toluene (2 mL) under inert atmosphere was added PPh3 (0.03
mmol). This solution was added to a mixture of the diboron reagent
(1.1 mmol) dissolved in toluene (4 mL). The alkyne (1 mmol) was
added to the solution and left until the reaction was complete. Puri-
fication was carried out by filtration over Celite and recrystalliza-
tion with cold hexane.
(14) (a) In Organofluorine Compounds in Medicinal Chemistry
and Biomedical Applications; Filler, R.; Kobayashi, Y.;
Yagupolskii, L. M., Eds.; Elsevier: Amsterdam, 1993.
(b) In Fluorine Containing Amino Acids: Synthesis and
Properties; Kukhar, V. P.; Soloshonok, V. A., Eds.; John
Wiley and Sons: Chichester, 1995. (c) In Biomedical
Frontiers of Fluorine Chemistry; Ojima, L.; McCarthy, J.
R.; Welch, J. T., Eds.; American Chemical Society:
Washington DC, 1996.
(15) (a) In Synthetic Fluorine Chemistry; Olah, G. A.; Chambers,
R. D.; Prakash, G. K. S., Eds.; John Wiley and Sons: New
York, 1992. (b) Banks, R. E.; Smart, B. E.; Tatlow, J. C. In
Organofluorine Chemistry: Principles and Commercial
Applications; Plenum Press: New York, 1994.
(16) Welch, J. T.; Eswarakrishnan, S. In Fluorine in Bioorganic
Chemistry; John Wiley and Sons: New York, 1991.
(17) Lal, G. S.; Pez, G. P.; Syvret, R. G. Chem. Rev. 1996, 96,
1737.
(18) Prakash, G. K. S.; Hu, J.; Olah, G. A. J. Fluorine Chem.
2001, 112, 357.
(19) Nyffeler, P. T.; Gonzalez Durón, S.; Burkart, M. D.;
Vincent, S. P.; Wong, C.-H. Angew. Chem. Int. Ed. 2005, 44,
192.
(20) Umemoto, T.; Fukami, S.; Tomizawa, G.; Harasawa, K.;
Kawada, K.; Tomita, K. J. Am. Chem. Soc. 1990, 112, 8563.
(21) Lal, G. S. J. Org. Chem. 1993, 58, 2791.
(22) Xu, Z.; DesMarteau, D. D.; Gotoh, Y. J. Chem. Soc., Chem.
Commun. 1991, 179.
Method B: To a sample of [Pt(PPh3)4] (0.025 mmol) dissolved in
DMF (2 mL) under inert atmosphere was added a mixture of the di-
boron reagent (1.1 mmol) dissolved in toluene (4 ml). The alkyne (1
mmol) was added to the solution and stirred at 80 °C until reaction
was complete. Then the reaction mixture was diluted with benzene,
repeatedly washed with cold water to remove DMF, and finally
dried over anhyd MgSO4. Kugelrohr distillation gave the alkenyl di-
boronate.
Electrophilic Fluorination of Alkenyl Diboronates; Typical
Procedure
To a solution of alkenyl diborane (1 mmol) in MeCN (6 mL), under
inert atmosphere, Selectfluor (2 equiv) was added and the reaction
mixture stirred at r.t. for 15 h. Then the solvent was removed under
reduced pressure. The residue was treated with aq NaOH (5 mL, 1.0
M) and extracted with Et2O (3 × 10 mL).
Acknowledgment
The authors thank the CTQ2004-04412/BQU for financial support
and the Generalitat de Catalunya for a studentship to J. R.
(23) Banks, R. E.; Lawrence, J. J.; Popplewell, A. L. J. Chem.
Soc., Chem. Commun. 1994, 343.
(24) Zupan, M.; Iskra, J.; Stavber, S. J. Org. Chem. 1995, 60, 259.
(25) Stavber, S.; Zupan, M. Synlett 1996, 693.
(26) Greedy, B.; Gouverneur, V. Chem. Commun. 2001, 233.
(27) Matthews, D. P.; Miller, S. C.; Jarvi, E. T.; Sabol, J. S.;
McCarthy, J. R. Tetrahedron Lett. 1993, 34, 3057.
(28) Petasis, N. A.; Yudin, A. K.; Zavialov, I. A.; Prakash, G. K.
S.; Olah, G. A. Synlett 1997, 606.
References
(1) (a) Brown, H. C. In Hydroboration; Wiley-Interscience:
New York, 1962. (b) Brown, H. C. In Boranes in Organic
Chemistry; Cornell University Press: Ithaca, 1972.
(c) Brown, H. C. In Organic Synthesis via Boranes; Wiley-
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