ElectronTransfer,RadicalAddition,FreeRadicalReactions
J. Chin. Chem. Soc., Vol. 48, No. 6B, 2001 1133
radicaladditionorfromtheproduct2e byanelectrontransfer
pro cess. If the prod uct2b all co mes from the prod uct1b, that
means the en tire com pound1b con verts to the prod uct 2b,
since the yields of the prod uct1b are zero in the course of the
reaction.Thereactionproceedstheelectrontransferprocess,
and then the yield of the prod uct3 should be near one half of
that of the prod uct 2b. How ever, the yields of the prod uct 3
are al most equal to those of the prod uct2batdifferentreac-
tion times in DMSO or THF (Ta ble 2). The yields of the prod-
uct 3 are greater than the ex pected val ues. This in di cates that
the prod uct 3 is not only con trib uted from equa tion (12). The
yield of the prod uct3 would not be af fected if the prod uct2b
co mes from the prod uct 1b, but the yield of the prod uct 3
would in crease if the prod uct2b is con verted from the prod-
uct 2e viatheelectrontransferprocess. Thismightimplythat
there is an other elec tron trans fer pro cess in the mech a nism
be sides that in equa tion (12). The prod uct 1b was not ob-
served in the course of the re ac tion, and the yields of the prod-
uct 2e de creased while the yields of the prod uct 2bincreased.
This might in di cate that the com pound 2b might be de rived
from the prod uct 2e by the elec tron trans fer pro cess. We
might con clude that the prod uct 2b would be con trib uted
from two sources, one is from the prod uct2e via the elec tron
trans fer pro cess and the other is from the prod uct1b by free
radicaladdition. Itisstillunclearwhatcausesthedifference
between the photolytic reaction of the com pound 1e in
furan were dis tilled from so dium metal. Other sol vents were
purchased and used withoutpurification. Allyl chloride,
2-methylallylchloride, 2-chloroallylchloride, 2-chlorometh-
yl allyl chlo ride, 2-(trimethylsilylmethyl)allyl chlo ride, and
t-butyl chlo ride, TEMPO(2,2,6,6-tetramethyl-1- piperidinyl-
oxy, free rad i cal), hexamethyldisilane, and hexamethyl disil-
oxane, biphenyl were purchased from Aldrich Chemical
Com pany. In most cases, the re agents were used with out fur-
therpurification.Organomercurialsweresynthesizedbythe
1
7
standardGrignardprocedure.
General Procedure for Photostimulated Reactions of
2-SubstitutedAllyl Chloride with t-Butylmercury Chlo-
ride in Different Solvents (Tables 1 and 2)
2-substitutedallyl chlo ride (1.0 mmol), t-BuHgCl (0.1
mmol) and in ter nal stan dard (0.05 mmol of biphenyl) were
dis solved in 1 mL of ni tro gen-purged dry sol vents. The so lu-
tion was di vided into four dry and ni tro gen-purged quartz
tubes (0.25 mL in each tube) with each equipped with a rub-
o
ber sep tum. The tubes were ir ra di ated at 35-40 C with a 100
W UV lamp placed about 20 cm from the re ac tion tubes. Re-
ac tion tubes were re moved at var i ous times and the yields of
thesubstitutionproductsweredeterminedbygaschromatog-
raphy.Identificationofsubstitutionproductswasconfirmed
by com par i son of their GCMS data with those of the au then-
ticcompoundssynthesizedbythemethodsreportedinthelit-
1
8
CH
3
CN and in DMSO.
erature. The fol low ing prod ucts were ob tained from the re-
2
actionsoutlinedinTable1.4,4-Dimethyl-1-pentene ( 2a): bp
o
1
7
3
1-72 C/760 mmHg; H NMR (300 MHz, CDC1 ) 6.0-5.6
EXPERIMENTALSECTION
(m, 1 H), 5.1-4.9 (m, 2 H), 1.92 (d,J = 7.5 Hz, 2 H), 0.87 (s, 9
H); GCMS m/z (rel a tive in ten sity) 98 (M , 1), 83 (2), 57
+
Analyticalgaschromatographywasperformedusinga
(100), 55 (30), 41 (48), 39 (15). 2,4,4-trimethyl-1-pentene
o
1
Perkin-Elmer Autosystem with a DB-5 col umn (0.25 M, 60
(2b): bp 101-103 C/760 mmHg; H NMR (300 MHz, CDC1 )
3
1
M)andaflameionizationdetector. H NMR spec tra were re-
4.83 (s, 1H), 4.63 (s, 1H), 1.94 (s, 2H), 1.77 (s, 3H), 0.93 (s,
+
cordedona300MHzVXRFT-NMRspectrometerwithtetra-
methylsilane as the in ter nal stan dard. GCMS were re corded
on a Quattro GCMS 5022 spec trom e ter or HP 5890 Se ries II
Gas Chromatograph with HP 5972A MSD. Melting points
were determined on a Thomas-Hoover capillary melting
point ap pa ra tus and were un cor rected. GLC yields were de-
ter mined by us ing an in ter nal stan dard (biphenyl) and were
correctedwithpredeterminedresponsefactors.
9H); GCMS (EI) m/z (relativeintensity)112(M , 16.18), 97
(18), 57 (100), 55 (56). 2-chloro-4,4-dimethyl-1-pentene
1
(2c): H NMR (300 MHz, CDC1
3
)
5.26 (s, 1H), 5.06 (s, 1H),
2.26 (s, 2H), 1.0 (s, 9H); GCMS (EI) m/z(relativeintensity)
+
+
134 ((M+2) , 1.01), 132 (M , 3.14), 117 (5), 57 (100), 53
(11), 41 (71). 2-chloromethyl-4,4-dimethyl-1-pentene (2d):
1
H NMR (300 MHz, CDC1 ) 5.28 (s, 1H), 4.96 (s, 1H), 4.06
3
(s, 2H), 2.10 (s, 2H), 0.94 (s, 9H); GCMS (EI) m/z(relative
+
+
intensity)148((M+2) , 0.29), 146 (M , 0.79), 133 (1.79), 131
Materials
(7), 110 (10), 95 (50), 67 (30), 57 (100), 53 (45), 41 (79).
1
Solvents were purchased from Riedel-de Haen and
Mallinckrodt. Dimethyl sulfoxide (DMSO) and acetonitrile
were dis tilled from cal cium hy dride and stored over 4A mo-
lecularsievesundernitrogen;diethylether, andtetrahydro-
2-trimethylsilylmethyl-4,4-dimethyl-1-pentene (2e):
NMR (300 MHz, CDC1
H
3
) 4.51 (s, 1H), 4.13 (s, 1H), 1.86 (s,
2H), 1.57 (s, 2H), 0.93 (s, 9H), 0.02 (s, 9H); GCMS (EI) m/z
+
(relativeintensity)169((M-15) , 3.9), 128 (14), 73 (100), 57