Hz), 3.4 (1 H, dt, J 9.0 and 3.4 Hz), 2.3–2.0 (2 H, m), 2.08 (3 H, s), 2.0 1.4
(8 H, m).
electron rich ones, such as dihydropyran, provided diacetoxy
and dithiocyanate derivatives as the main products; this latter
reactivity may be ascribed to the high stability of the cationic
intermediate. Styrene derivatives immediately underwent a
polymerisation process when they were dissolved in HFP; this
phenomenon is probably catalysed by the acidity of the reaction
medium. All the collected data are in agreement with the
suggested reaction mechanism.
In conclusion, our studies on the reactivity in HFP show it to
be very promising, and the results broaden the utility of BAIB,
opening a route to new synthetic applications in organic
chemistry. Research in this field is currently in progress, since
acetoxy thiocyanate and dithiocyanate derivatives have been
shown to possess good fungicidal activity.
13C NMR spectra (CDCl3) for 2a: 171.0 (CNO), 112.5 (SCN), 72.2, 37.8,
33.2, 31.4, 28.4, 29.6, 22.4, 21.0, 13.9. For 2b: 171.0 (CNO), 110.4 (SCN),
66.1, 48.9, 33.2, 31.4, 28.4, 29.6, 22.4, 21.0, 13.9. For 6a: 170.5 (CNO),
111.1 (SCN), 74.9, 51.5, 32.6, 32.3, 25.7, 23.8, 21.1. For 7a: 170.5 (CNO),
111.8 (SCN), 77.8, 54.6, 32.5, 32.0, 27.8, 25.7, 22.3, 21.2.
IR spectra (CHCl3, cm21) for 2a: 2140 (SCN, sharp peak), 1733 (CNO,
broad peak). For 2b: 2140 (SCN, sharp peak), 1735 (CNO, broad peak). For
6a: 2175 (SCN, sharp peak), 1730 (CNO, broad peak). For 7a: 2145 (SCN,
sharp peak), 1730 (CNO, broad peak).
References
1 B. Allard, A. Casadevall, E. Casadevall and C. Largeau, Nouv. J. Chem.,
1979, 3, 995; F. L. Schadt, T. W. Bentley and P. V. R. Schleyer, J. Am.
Chem. Soc., 1976, 98, 7667.
2 C. Reichardt, Solvent and Solvent Effect in Organic Chemistry, Verlag
Chemie, Veinhein, 1988.
3 L. Eberson, M. P. Hartshorm and O. Persson, J. Chem. Soc., Perkin Trans
2, 1995, 1735; 1995, 1331; L. Eberson, M. P. Hartshorm, F. Radner and
O. Persson, Chem. Commun., 1996, 215.
4 Y. Kita, H. Tohma, K. Hatanaka, T. Takada, S. Fujuta, S. Mitoh,
H. Sakurai and S. Oka, J. Am. Chem. Soc., 1994, 116, 861.
5 L. Eberson, M. P. Hartshorm and O. Persson, J. Chem. Soc., Perkin Trans
2. 1996, 141; 1996, 151.
Footnotes
* E-mail: piancatelli@axrma.uniroma1.it
† Typical experimental procedure: a solution of the alkene (1 mmol) in 4 ml
of HFP was treated with 1.2 mmol of KSCN and 4 mmol of BAIB and the
resulting reaction mixture is stirred at room temperature for 20 min. The
reaction was quenched with saturated aqueous Na2S2O3 (5 ml) and
extracted with EtOAc (4 3 5 ml). The combined organic extracts were
washed with aqueous NaHCO3 and brine, dried over anhydrous Na2SO4,
and concentrated under reduced pressure. Column chromatography on SiO2
(light petroleum–EtOAc) afforded pure products.
1H NMR spectra (CDCl3) for 2a: 5.1 (1 H, m), 3.2 (1 H, dd, J 3.9 and 14.0
Hz), 3.0 (1 H, dd, J 6.5 and 14.0 Hz), 2.1 (3 H, s), 1.9–1.1 (10 H, m), 0.85
(3 H, t). For 2b: 4.3 (1 H, dd, J 5.1 and 12.0 Hz), 4.2 (1 H, dd, J 7.2 and 12.0
Hz), 3.3 (1 H, m), 2.1 (3 H, s), 1.9–1.1 (10 H, m), 0.85 (3 H, t). For 6a: 4.7
(1 H, dt, J 10.3 and 4.6 Hz), 3.1 (1 H, dt, J 10.3 and 4.3 Hz), 2.3–2.0 (2 H,
m), 2.06 (3 H, s), 1.9–1.1 (6 H, m). For 7a: 4.9 (1 H, ddd, J 9.0, 3.7 and 7.4
6 A. De Mico, R. Margarita, A. Mariani and G. Piancatelli, Tetrahedron
Lett., 1996, 37, 1899.
7 R. A. Moriarty, R. K. Vaid and G. F. Koser, Synlett, 1990, 2, 365.
8 C. A. Ramsden, Chem Soc. Rev., 1994, 23, 111.
Received in Cambridge, UK, 24th March 1997; Com.
7/01998J
1238
Chem. Commun., 1997