Transition Met Chem
n
C5Me4R)MoI(CO)3] (R = Bu), complex (2) as purple-red
reactivity of alcohols was generally poor. Aromatic sub-
strates containing electron-donating groups were beneficial
for improving the alkylation yields, consistent with an
aromatic electrophilic substitution reaction. On the basis of
the para/ortho and Markovnikov selectivities observed for
the products, the oxidation of the molybdenum complex by
o-chloranil to give an intermediate molybdenum cate-
cholate species is postulated. Compared with traditional
catalysts, the present system has significant practical
advantages: lower amounts of catalyst, mild reaction con-
ditions, high selectivity, avoidance of isomerization, and
ease of use. Further studies to elucidate the reaction
mechanism and expand the synthetic utility of these alky-
lation catalyses are ongoing.
crystals in 82.8 % yield. M.p.: 104–105 °C; Anal. Calc. for
C16H21MoIO3: C, 39.7; H, 4.3. Found (%): C, 39.5; H, 4.4;
1H NMR (CDCl3, 500 MHz): d 0.93 (t, 3H, J = 6.75 Hz,
CH3), 1.34-1.38 (m, 4H, (CH2)2), 2.16 (d, 12H, J = 2.0 Hz
C5Me4), 2.42 (t, 2H, J = 7.25 Hz, C5Me4CH2); 13C
NMR(CDCl3, 125 MHz):d 11.3, 11.4, 13.9, 22.8, 26.1,
33.2, 106.6, 108.5, 110.6; IR (KBr): 2021(s), 1938(s),
1921(w), 2955, 2928, 2866(w), 1465(w), 1450(w),
1380(w) cm-1
.
Synthesis of complex (3)
Using a procedure similar to that described above, reaction
of the molybdenum dimer [(g5-C5Me4R)Mo(CO)3]2
t
(R = Bu) with I2 in chloroform afforded [(g5-C5Me4-
R)MoI(CO)3] (R = Bu), complex 3 as purple-red crystals
Experimental
t
in 56.6 % yield. M.p.: 99-100 °C; Anal. Calc. for C16-
H21MoIO3: C, 39.7; H, 4.3. Found (%): C, 39.5; H, 4.2; 1H
NMR (CDCl3, 500 MHz): d 1.38 (s, 9H, C(CH3)3), 2.09 (s,
6H, C5Me2), 2.31 (s, 6H, C5Me2); 13C NMR (CDCl3,
125 MHz): d 11.5, 15.1, 32.5, 34.6, 108.2, 108.3, 120.1; IR
(KBr): 1380(w), 1390, 1396, 1456(w), 2870, 2969 (w),
All reactions were carried out under an argon atmosphere
using standard Schlenk techniques. Solvents were distilled
from appropriate drying agents under an argon atmosphere.
1H and 13C NMR spectra were recorded on a Bruker AV
500 instrument in CDCl3, while IR spectra were recorded
as KBr disks on an IR FT 8900 spectrometer. Gas chro-
matograms were recorded with an Agilent 6820 gas chro-
matograph. Mass spectrometric measurements were
1932 (s), 1953 (s), 2017 (s) cm-1
.
Synthesis of complex (4)
performed on
spectrometer.
a
DSQ(II) gas chromatograph–mass
Using a procedure similar to that described above, reaction
of [(g5-C5Me4R)Mo(CO)3]2 (R = Ph) with I2 in chloro-
form afforded [(g5-C5Me4R)MoI(CO)3] (R = Ph), com-
plex 4 as purple-red solid in 75.4 % yield. M.P.:
112–113 °C; Anal. Calc. for C18H17MoIO3: C, 42.9; H,
3.8. Found (%): C, 42.6; H, 3.7; 1H NMR (CDCl3,
500 MHz): d 2.18 (s, 6H, C5Me2), 2.19 (s, 6H, C5Me2),
7.28–7.43 (m, 5H, C6H5); 13C NMR (CDCl3, 125 MHz): d
11.3, 12.5, 107.6, 108.6, 113.1, 128.4, 128.5, 130.9, 131.2;
IR (KBr): 702(s), 762(s), 1465(w), 1580, 3248(w), 1930
Synthesis of complex (1)
[(g5-C5Me4R)Mo(CO)3]2 (R = allyl) (0.068 g, 0.10 mmol)
was mixed with excess I2 (0.033 g, 0.13 mmol) in chlo-
roform (20 mL). The solution was stirred at room tem-
perature overnight and then washed with 10 % sodium
thiosulphate (10 mL). After removal of solvent, the residue
was placed on an alumina column. Elution with petroleum
ether/CH2Cl2 (2:1) developed a purple-red band that
afforded [(g5-C5Me4R)MoI(CO)3] (R = allyl) (1) as a
purple-red solid, yield: 0.08 g (85.5 %). M.p. 90–91 °C.
Anal. Calc. for C15H17MoIO3: C, 38.5; H, 3.6. Found (%):
C, 38.6; H, 3.7; 1H NMR (CDCl3, 500 MHz): d 2.11 (br s,
6H, C5Me2), 2.24 (br s, 6H, C5Me2), 7.29–7.38 (m, 5H,
C3H5); 13C NMR(CDCl3, 125 MHz): d 11.3, 11.4, 30.4,
107.5, 107.6, 108.2, 116.4, 134.9; IR (KBr): 1950(s),
2025(s), 2048(w), 3171(vw), 1654 (w), 2856, 2922, 883(s),
(s), 1955 (s), 2019 (s) cm-1
.
Synthesis of complex (5)
Using a procedure similar to that described above, reaction
of [(g5-C5Me4R)Mo(CO)3]2 (R = Bz) with I2 in chloro-
form afforded [(g5-C5Me4R)MoI(CO)3] (R = Bz), com-
plex 5 as purple-red crystals in 65.8 % yield. M.P:
115–116 °C; Anal. Calc. for C19H19MoIO3: C, 44.0; H,
3.7. Found(%): C, 44.1; H, 3.5; 1H NMR (CDCl3,
500 MHz): d 2.13 (s, 6H, C5Me2), 2.15 (s, 6H, C5Me2),
3.77 (s, 2H, CH2), 7.11-7.34(m, 5H, C6H5); 13C NMR
(CDCl3, 125 MHz):d 11.5, 11.8, 32.0, 107.7, 108.4, 108.7,
126.7, 127.8, 128.8, 139.4; IR (KBr): 3024, 1580, 1490,
914(s) cm-1
.
Synthesis of complex (2)
Using a procedure similar to that described above, reaction
of the molybdenum dimer [(g5-C5Me4R)Mo(CO)3]2
2920, 2858, 1460, 2019(s), 1944(s), 1925(w) cm-1
.
n
(R = Bu) with I2 in chloroform afforded [(g5-
123