ORDER
REPRINTS
302
LABUSCHAGNE ET AL.
with ether–petroleum ether (4:1) yielded 1,3,5-triethoxycarbonylpenta-2,4-
dienylidenetriphenylphosphonium ylide (4) (1.71 g, 55%), m.p. 121.5ꢀC (from
ether); dH 0.92 (t, JHH 7.1 Hz, 3H), 1.05 (t, JHH 7.1 Hz, 3H), 1.25 (t, JHH
7.1 Hz, 3H), 3.94 (q, JHH 7.1 Hz, 2H), 3.99 (q, JHH 7.1 Hz, 2H), 4.16
(q, JHH 7.1 Hz, 2H), 6.40 (d, JHH 15.7 Hz, ¼CH), 7.25 (d, JPH 18.8 Hz,
¼CH), 7.71 (d, JHH 15.8 Hz, ¼CH), 7.50–7.91 (m, arom.H, 15H); dC
14.09(CH3), 14.37 (CH3), 14.50(CH3), 59.28(CH2), 59.35(CH2), 59.85(CH2),
63.70 (d, JPC 115.7 Hz, P¼C<), 109.98 (d, JPC 14.4 Hz, ¼C<), 113.0 (¼CH),
124.45 (d, JPC 91.9 Hz, 3 Â arom. C), 129.05 (d, JPC 12.4 Hz, 6 Â m-arom. C),
132.79 (d, JPC 2.7 Hz, 3 Â p-arom. C), 133.87 (d, JPC 9.6 Hz, 6 Â o-arom. C),
142.18 (¼CH), 149.18 (d, JPC 15.5 Hz, ¼CH), 167.51 (>C¼O), 167.66
(>C¼O), 167.71 (>C¼O); Mþ, 544.2023. Calcd. for C32H33O6P : M,
544.2014; Found: C, 70.40; H, 6.10. Required: C, 70.58; H, 6.07.
2. Condensation of 1,3-Diethoxycarbonylallylidenetriphenylphospho-
nium Ylide (3) with Ethyl Propynoate (2) in a Molar Ratio of 1 : 3: The
phosphonium ylide (3) (4.46 g, 10 mmol) and ethyl propynoate (2) ( 3 g,
30 mmol) in chloroform (15 cm3) were heated for 117 h at 40ꢀC in a glass
pressure vessel, the solvent evaporated under reduced pressure at 30ꢀC and
the residue chromatographed on silica gel. Elution with ether–petroleum
ether (2 : 3), ether–petroleum ether (4 : 1) and ethanol–ether (3 : 1), respec-
tively, yielded the following three fractions:
(a) 1,3,5-triethoxycarbonylbenzene (5)3 (0.64 g, 22%), m.p. 135ꢀC
(from ether–petroleum ether)3; Found: C, 61.10; H, 5.80. Calcd. for
C15H18O6: C, 61.22; H, 6.12; 1,2,4-triethoxycarbonylbenzene (6) (0.17 g,
6%), b.p. 150ꢀC (air-bath temp.)/0.05 mm Hg; dH 1.38 (t, J 7.0 Hz, 6H), 1.41
(t, J 7.0 Hz, 3H), 4.40 (q, J 7.1 Hz, 4H), 4.42 (q, J 7.1 Hz, 2H), 7.74 (dd, J 8.0
and 0.6 Hz, H6), 8.20 (dd, J 8.0 and 1.7 Hz, H5), 8.40 (dd, J 1.7 and 0.5 Hz,
H3); dC 14.07 (CH3), 14.12 (CH3), 14.28 (CH3), 61.69 (CH2), 61.94 (CH2),
62.0 (CH2), 128.87 (arom. C), 130.11 (arom. C), 131.99 (arom. C), 132.13
(arom. C), 132.72 (arom. C), 136.29 (arom. C), 164.99 (>C¼O), 166.61
(>C¼O), 167.14 (>C¼O); Mþ, 294.1099. Calcd. for C15H18O6 : M,
294.1103; Found: C, 61.05; H, 6.0. Required: C, 61.22; H, 6.12;
(b) 1,3,5-triethoxycarbonylpenta-2,4-dienylidenetriphenylphosphonium
ylide (4) (3.02 g, 56%); (c) the third fraction was subjected to further
purification by chromatographic separation on a chromatotron with ethanol–
dichloromethane (3 : 7) as eluent to yield 2,4-diethoxycarbonyl-6-triphenyl-
phosphoniumphenoxide (7) (0.42 g, 9%), m.p. 206ꢀC (from ether); dH 1.26 (t,
J 7.1 Hz, 3H), 1.33 (t, J 7.1 Hz, 3H), 4.20 (q, J 7.1 Hz, 2H), 4.32 (q, J 7.1 Hz,
2H), 7.49–7.69 (m, arom. C, 15H), 7.63 ðdd, JPH 15:9 Hz, JH H 2:65 Hz, H5Þ,
5
3
5
8.69 ðdd, JH H 2:5 Hz and JPH 0:6 Hz, H3Þ; dC 14.40 (CH3), 14.52 (CH3),
3
5
3
60.03 (2 Â CH2), 107.02 (d, JPC 101.3 Hz, C6), 110.88 (d, JPC 16.0 Hz, C4),
121.18 (d, JPC 7.1 Hz, C2), 121.94 (d, JPC 92.4 Hz, 3 Â arom.C), 129.39