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LETTER
(12) Freeman, P. K.; Johnson, R. C. J. Org. Chem. 1969, 34, 1746.
Experimental procedure for preparation of 4 To a solution of
Experimental procedure for preparation of 6. The crude prod-
uct was a red/brown oil which was purified by flash chroma-
tography on silica to yield 6 as a yellow oil. Yield: 45%. The
NMR data for 6 were identical with those in the literature.11
Experimental procedure for reaction of 4 with methyl benzo-
ate. Work-up as for 6 gave a mixture of products (Scheme 3).
Yield: 42%. 1H NMR (CDCl3)12 d 7.89-6.95 (m, 10H, 2xPh
from E and Z), 6.05 (s, 0.9H, Z CH), 5.76 (s, 0.1H, E CH), 3.81
(s, 0.3H, E CH3), 3.58 (s, 2.7H, Z CH3).
Experimental procedure for reaction of 4 with phenyl acetate.
Work-up as for 6 gave a mixture of products (Scheme 3).
Yield: 55%. 1H NMR (CDCl3) d 7.65-7.20 (m, 10H, 2xPh),
5.93 (s, 0.57H, CH), 5.88 (s, 0.43H, CH), 2.21 (s, 1.71H,
CH3), 2.01 (s, 1.29H, CH3).
Experimental procedure for preparation of 8. No carbonyl
compound was added. Instead of dilution, the solvent was re-
moved in vacuo to yield 8 as an unstable brown solid. 1H NMR
(C6D6) d 7.25 (m, 1H, Ph), 7.04 (m, 2H, Ph), 6.68 (m, 2H, Ph),
6.48 (m, 1H, C5H4), 5.88 (m, 1H, C5H4), 5.76 (s, 5H, Cp), 4.70
(m, 1H, C5H4), 4.34 (m, 1H, C5H4), 2.14 (s, 3H, CH3), 1.63 (d,
J = 9.8Hz, 1H, CH2Ph), 1.36 (d, J = 9.8Hz, 1H, CH2Ph), 0.76
(s, 3H, CH3), 0.52 (d, J = 8.9Hz, 1H, Hb), -3.0 (d, J = 8.9Hz,
1H, Ha). 13C NMR d 154.62 (quat. Ph), 137.64 (quat. C5H4),
129.84 (Ph), 125.58 (Ph), 125.38 (Ph), 116.96 (C5H4), 116.65
(C5H4), 112.37 (Cp), 108.97 (C5H4), 104.80 (C5H4), 51.82
(CH2Ph), 33.90 (quat.), 31.57 (CH3), 29.99 (CH3), 29.96
(CH2).
t
Ti(h5-C5H5)(h5-C5H4 Bu)Cl210 (1g, 0.65mmol) in diethyl ether
(30mL) at -40 °C was added benzyl magnesium bromide
(6.6mL of a 1M solution in diethyl ether), dropwise with stir-
ring. The mixture was stirred for 5h, allowed to warm to room
temperature and the solvent was removed in vacuo. The resul-
ting residue was extracted with petroleum ether (15mL) and
filtered. The solution was concentrated to 20mL and cooled to
-30° C to yield 4 as a brown powder, mp 41° C (dec.). Yield:
0.8g, 60%. 1H NMR (C6D6): d 7.26 (m, 4H, Ph), 6.98 (m, 2H,
Ph), 6.90 (m, 4H, Ph), 5.96 (m, 2H, C5H4), 5.75 (s, 5H, Cp),
5.67 (m, 2H, C5H4), 2.22 (d, J = 9.3Hz, 2H, CH2), 1.91 (d, J =
9.3Hz, 2H, CH2), 0.94 (s, 9H, tBu). 13C NMR d 154.03 (quat.
Ph), 139.22 (quat. C5H4), 125.53 (2xPh), 121.53 (Ph), 115.38
(Cp), 114.87 (C5H4), 113.71 (C5H4), 73.73 (CH2), 32.50
(quat.), 31.14 (CH3).
General Procedure for Thermolysis of 4. Thermolysis reac-
tions were carried out according to the procedure described by
Petasis,5 using 0.25 mmol of 4.
Experimental procedure for preparation of 5. Acetonitrile was
used in place of toluene as solvent. Instead of dilution, the sol-
vent was removed in vacuo to leave a dark red residue which
was washed with petroleum ether (2 x 15ml) to yield the un-
stable product 5. 1H NMR (C6D6): d 7.34 (m, 2H, Ph), 7.02 (m,
2H, Ph), 6.70 (m, 1H, Ph), 5.82 (m, 1H, C5H4), 5.67 (m, 1H,
C5H4), 5.52 (m, 1H, C5H4), 5.47 (s, 5H, Cp), 5.42 (m, 1H,
C5H4), 2.77 (s, 6H, 2xCH3), 1.28 (s, 9H, tBu).
Synlett 1999, No. 1, 90–92 ISSN 0936-5214 © Thieme Stuttgart · New York