M. Biagetti et al. / Tetrahedron 58 -2002) 5023±5038
5037
presence of catalyst B $entry 4, Table 3), was puri®ed by
MPLC on silica gel, using toluene as eluant, to give in 30%
yield compound 21d as a pale yellow liquid. MS, m/z: 356
$82), 354 $71), 285 $100), 283 $70), 229 $63), 162 $42), 113
$58). IR $®lm): n 1737, 1628, 1533, 1493, 1088, 999,
162.8, 141.7, 131.2 $2C), 128.5, 128.3 $2C), 122.6, 122.3,
101.0, 93.4, 82.8, 32.5, 31.2, 26.9, 22.3, 16.4, 13.9 ppm.
Anal. Calcd for C19H20O2: C, 81.40; H, 7.19. Found: C,
81.47; H, 7.25. Concentration of the last eluted chromato-
graphic fractions allowed isolation of 42 $52 mg, 5% yield)
as a pale yellow liquid. MS, m/z $%): 266 $34), 210 $16), 209
$100), 153 $8), 152 $10), 139 $32), 105 $9). IR $®lm): n 2216,
1
833 cm21. H NMR $200 MHz, CDCl3): d 7.66 $1H, s),
7.43 $2H, d, J8.5 Hz), 7.21 $2H, d, J8.5 Hz), 2.48 $2H,
t, J7.5 Hz), 1.69 $2H, pseudo-quint, J7.0 Hz), 1.40±1.15
$4H, m), 0.87 ppm $3H, t, J6.0 Hz). 13C NMR $50 MHz,
CDCl3): d 162.6, 158.3, 147.1, 134.3, 133.0, 130.1 $2C),
129.0 $2C), 117.5, 108.4, 31.2, 31.1, 27.2, 22.1, 13.8 ppm.
Anal. Calcd for C16H16BrClO2: C, 54.03; H, 4.53. Found: C,
53.89; H, 4.42.
1743, 1542, 1490, 1080, 823, 756 cm21
.
1H NMR
$200 MHz, CDCl3): d 7.60±7.20 $6H, m), 6.21 $1H, d,
J9.5 Hz), 2.81 $2H, t, J7.5 Hz), 1.79 2H, pseudo-quint,
J7.5 Hz), 1.45±1.20 $4H, m), 0.93 ppm $3H, t, J6.5 Hz).
13C NMR $50 MHz, CDCl3): d 170.1, 161.0, 145.8, 131.2
$2C), 128.6, 128.4 $2C), 122.4, 112.9, 101.0, 93.9, 82.4,
32.9, 31.2, 26.8, 22.3, 13.9 ppm. Anal. Calcd for
C18H18O2: C, 81.17; H, 6.81. Found: C, 81.31; H, 6.97.
4.7.5. 4,6-Dipentyl-5-phenyl-2ꢀ2H)pyranone ꢀ21e). The
crude reaction product, which was obtained byiodolactoni-
zation of 15d in 1,2-dichloroethane followed bytreatment
with phenyltributyltin $41c) in the presence of catalyst B
$entry5, Table 3), was puri®ed byMPLC on silica gel,
using a mixture of petroleum ether and AcOEt $95:5) as
eluant, to give compound 21e in 38% yield as a pale yellow
liquid. MS, m/z $%): 312 $22), 256 $37), 228 $100), 227 $23),
185 $18), 171 $15), 55 $18). IR $®lm): n 1731, 1631, 1544,
1444, 1006, 769, 705 cm21. 1H NMR $200 MHz, CDCl3): d
7.45±7.35 $3H, m), 7.16±7.10 $2H, m), 6.07 $1H, s), 2.23
$2H, t, J7.7 Hz), 2.10 $2H, t, J7.5 Hz), 1.57 $2H, pseudo-
quint, J7.5 Hz), 1.34 $2H, pseudo-quint, J7.5 Hz), 1.25±
1.05 $8H, m), 0.83±0.75 ppm $6H, m). 13C NMR $50 MHz,
CDCl3): d 162.8, 162.1, 160.6, 134.3, 130.0 $2C), 128.5
$2C), 127.9, 119.1, 109.8, 33.4, 31.6, 31.1 $2C), 27.6,
27.2, 22.1 $2C), 13.8, 13.7 ppm. Anal. Calcd for
C21H28O2: C, 80.73; H, 9.03. Found: C, 80.86; H, 9.12.
Acknowledgements
This work was supported bythe Ministero dell'Istruzione,
Á
dell'Universita e della Ricerca $MIUR) and the University
1
Â
of Pisa. We thank Dr Stephane Viel for obtaining the H
NMR spectra at 600 MHz and the 13C NMR spectra at
150 MHz and Professor Annalaura Segre for the use of
NMR facilities of the Servizio NMR dell'Area della Ricerca
di Roma $CNR). We are also grateful to Mr Piergiorgio
Vergamini for recording IR spectra.
References
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pseudo-quint, J7.5 Hz), 1.45±1.30 $4H, m), 0.92 ppm
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È
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