close

Вход

Забыли?

вход по аккаунту

?

Intramolecular Photocyclization of -Diphenyl-(1)-alken-1-ols by an Exciplex Quenching Mechanism.

код для вставкиСкачать
COMMUNICATIONS
E.yprrimcnt(i1 Proceduve
2: A s o l u t i ~ i of
i I (4.25 g, 10 mmol) in diethyl ether (30 mL) was treated with the
equiinolar quxntity o f lithium trrr-butyl amide at -30 -C. After the mixture had
heen warmed 10 20 C. the solvent was removed under vacuum. the resulting lithiiiin
chloride filtered. and the yellow residue taken up in iT-hexane (10 mL). Compound
2 crystalli/ed as line needles at -30 C.Yield: 3.45 g (72%). m.p. 83-85 C (decamp.): "P N M R ((.DCI,): S = 32 I ; ' H N M R (CDCI,): 6 =7.39 (s. W-CH).2.85
(d. .I = 4.7 Hr. NH). 1.54 (s). 1.42 (s). 1.28 (s), 1.21 (s). 0.93 (d, J = 0.9 Hz, each
rBu):MS(40eV):ni ~ ( % ) . 4 3 3 ( 1 2 ) [ Mi N,].418(41)[Mt - N1 - CHJ.362
(100) [ ( / B u N t H ) P = N A r ) + ]
3: 2 ( 3 g. 6 5 inmol) was dissolved in absolute DME (20 mL) and stirred for 2 h
under rellux. At the beginning of the reaction a violent evolution of nitrogen was
observed. Aftcr the solution had been concentrated and cooled to -30 C. the
aininohis(iniiiio)pho\phorane 3 wab isolated as a fine crystalline white solid. Yield:
1 3 g ( X I * ' , , ) , 1n.p. 95 98 C: "P NMR (CDCI,). 6 = 39.5; ' H N M R (CDCI,):
0 = 7 30 ( 5 . i i i - C H ) . 1 82 (d, J = 3.8 Hr. N H ) , 1.50 (s. o-C(CH,),). 1.36 (d,
J =7.2 Hi. iX(H)C(CH%)3).
1.27 (s. pC(CH3),). 1.15 (a. NC(CH,),): MS (40eV):
117 z ( % ) : -133 ( 2 1 ) [M'].
362 (100) [(rBuN(H)P=NAr)'].
4 : n B u L i ( 2 Y m L . I.6niinn-hexane)
.lowly added dropuise to a solution of the
bis(im1no)phosphorane 3 (2.0 g. 4.6 mmol) in D M E (20 mL)a t -60 C. After completc addimii the mixture was stirred for 1 b. The solution was then concentrated
to half t h c volume. Compound 4 precipitated at -30 C within t ~ weeks
o
in the
form of y e l l o u . prismatic crystals. Yield 0.9 g (37?%).
6: 5 (2.0 g. 3.X mmol) wa5 dissolved in T H P (50 mL) and treated with lithium
2.J.h-tri-/r,,-i-hutylphenqI amide (1.1 g. 3.8 minol). The solution was stirred
overnight. auhsequently all volatile components here removed under vacuum. The
residue was iakeii up i n tolucile (30 mL). and the lithium amide which had been
formed \ c i i j removed by filtration. The product 6 precipitated from the concentated
solution i n the form of pale yellow needlelike crystals. Yield: 2 4 g (84%). m.p.
167- I69 C. (dccomp.): "P NMR (C,D,:THF. 25 C ) : d = 22.1.
7: 6(1.00 g. 1.2 mmol) b a s dissolved in T H F (70 mL) and treated Mith ri-butyllithiuin (0 76 mL. 1 . 6 in~ ii-hexane). This resulted in the spontaneous precipitation of
7 'IL
. ..
'iii amorphous solid. The product was obtained in crystalline form by rrdissolv-
ing the precipitate a t 6 0 C. followed by slow cooling (10 C per h ) to rooin temperature Yield: 0.0 g (YO'!%), m.p. 92-93 C (decomp.): "P N M R (C,D,'THF):
c i = 41.3. ' H NMR (C,,D,,'DME): 6 =7.44 (s. 6H). 1.68 (s. 54 H ) . 1.40 (5. 27 H ) .
Received: Ma) 28. 1994 [Z69XOIE]
German version: Angrw . C/ien?. 1994. 106. 2170
[I] a ) D. _I. Harrrin. J. R. Hass. K. L. Bush. M. M. Bursey. F. Ramirer. S. Meyerson. J , d i n . C/iiw. Sor. 1979. IOi. 7409-7410: b) S. Meyerson. D. J. Harvan.
1. R. lia\s. F Ramirei. J. F. Marecek. ;hid 1984. /06. 6877-6883.
[2] t i ) S N Jcnny. .I. S. Ogden. J Chrm. S w . D d r o n Traiz.\. 1979. 1465- 1467:
h) L Bencrvenni. K . A. Gingerich, J. M o l . S/rui.r. 1983. 98. lY5.
[3] a ) J. M. Fiiedman. J R. Knoules. .I An?. Cheiii. Soc. 1985. 107, 6126 6127. b)
S. Freeinmi, J. M. Friedman. 1. R. Knowles. ihrd 1987. 109. 3166-3168; c)
1. M. I;i-iedinaii. S. Freeman. J. R. Knoules, ih;d 1Y88. 110. 1268-1275. and
i-eferenccs therein.
[4] a ) C'. Lcrch. J. Nicmann. W. W. Schoeller. P/io.\p/inrii.\ Scr//rir 1987. 30. 503:
h) A . StieriMieser. A. Raica. R. S. McDowell, R Cilaser. J. An?. Chrni. Soc.
1987. IOY. 41x4 418X; c ) M. W. Schmidt. R. N . Truoiig, M. S. Gordon, ihirl.
1987. I O Y . 5217 5237: d ) H Sun, D. A. Hrovat. T. W. Borden. rhid. 1987. 109.
5275 5276.
[5] R. Appcl. E Gaitrsch. F. Knoch. Angew. Cheii?. 1985. Y?. 574- 575: Angcii'.
(-'/ir,iii. //I/
Ed. €ii,y/. 1985. 34. 589-590.
[6] A nion~niericstructure w a s also assumed for the tetraphenvlarsonium salt of
tritliioinetaphosphate based on the results of field desorplion MS studies:
H . W Roesky. R Ahlrichs. S. Brode. Angrii. C%0?7 1986, YH. 91-93; ilnxcii..
('/wiii. I i i r €d. Eiig/ 1986. 35. 82-83,
[7] A lithium complex of it iminohis(methylene)met~iphospha~e
is k n o w n - R. Appel. P Schulte. F Knoch. P/io.sphorri.\, Sirlfrir 1988. 37, 195.198.
[XI E. Niecke. M. Nieger. V. von der Giinna. C/ieni. Bcr. 1990. 133. 2329-2333.
[Y] A. Ruhan. M. Nieger. E. Niecke. .4iigcn. C/WII.1993. 10.5. 1544-1545: Atigrw.
Chwi. /ill Ed. €nx/ 1993. 33, 1419-1420.
[lo] Crystal
structures
of
4
and
{7j :
[Li(C,H,,,o,)l[C,,H,.N,P]
([Li(c',H,o),]lC,,H,-N~P]i : ycllo\~crystals (yellou crystals] , crystal dimen~ i o n s O . 1 5 x O 4 0 x 0 . 4 5j0.35x0.35x0.50j mm:M = 529.7 :1104.6/: lriclinic
(hexagoiiall.spacegroupPT(no.2);P6,(no. 173)j.u = 8.908(5) [l5.116(3)].
h =I1 XXX(31. < =16.994(4) [18.735(7))A. x = X9.65(2). /j = 80.68(3).
77 -17(1) . I'= 1.733(1) j3.707(21: mi3. 2 = 2 [ 2 ; . p(Cuk,) = 0.89
(0.653 m r n - ' . 7 = 200 (193) K. F(000) = 584 [1220]. 7839 j2124) reflections
up t o 20,,,,,,= 130 120 w'ere measured hith Cu,, radiation on an Enraf-Nonius CAD4 diffractometer. or these 5891 [1884) were independent and were
used for a11 calculations. The structure was solved by direct methods and
refined anisotropically against F', the H atoms were refined with ii riding
model (SHELXL-93 [l I ] ) . I I R 2 ( F 2 )= 0.199 (0.2911 . R ( F ) = 0.067 [0.101) for
375 1768; parameters and 24 /201 restraints. An empirical ahsorption correction u i t h the program DIFABS 1121 was carried out for 4. One imino-rBu group
is disordered. A scmiempirical absorption correction based on Y scans war
carried out for 7 and the absolute structure was determined by Y refinement
[13]. The relatively high R value is attributed to the disorder of the p r B u group
and the T H F molecules. Further details of the crystal structurc inrestigations
may be obtained from the Fachinformations7entrum Karlsruhe. D-76344 Eggenstein-Leopoldshafen (FRG). on quoting the depository number CSD58351
[ l l ] G . M. Sheldrick, SHELXL-93. Universitat Giittingen. 1993.
[12] N. Walker. D. Stuart, Acru Crj.\/u//ogr. Swr. A 1983. 39. 158 166.
[I31 H. D. Flack. Actu Crj~slii//ogu.S r ~ rA. 1983. 39. 876-881.
[I41 a ) R. Detsch. E. Niecke. M. Nieger. W. W. Schoeller. C'hi~rti.Brr. 1992. f25.
1119-1124: b) M . Frost, Dissertation, Universitiit Bonn, 1994.
[15] E. Nicke. D. Ciudat in Mullipir Bonding i r n d Loll Courdinurioii n i P/insp/iiirri,\
Chrniisrri (Eds.: M. Regitr. 0. J. Scherer). Thieme. Stuttgart. 1990. pp. 392
404.
[I61 0 . Glemser. S. Pohl, F. M. Tesky. R. Mews. A n g r i i . C%rni. 1977. HY. 829 ~ 8 3 0 :
Anjicii.. Chw??.
I n r 6 1 . €nK/. 1977. 16. 789 790.
[I71 The calculations were carried out wiht the Gaussian 92 program. Gaussian 92.
Revision A : M. J. Frisch. G. W. Trucks, M. Head-Gordon. P. M. W. Gill.
M. W. Wong. J. B. Foresman. B G. Johnson. J. B. Schlegel. M. A. Robh, E. S
Replongle. R. Comperts, J. L. Andres. K. Raphavachari. J S. Biitkley. C.
Gonraler. R. L. Martin, D. J. Fox, D . J De Frees. J. Baker. .I. .IP. Stewart.
J. A. Pople. Gaussian Inc.. Pittsburgh, PA. 1992. All structures were characterized hy vibrational analysis (harmonic aprroximatioii).
1181 W. W. Schoeller. J. Strutwolf. E. Niecke. THEOCHC'M. wbmittcd.
~
Intramolecular Photocyclization of
o,o-Diphenyl-(o - 1)-alken-1-01s
by an Exciplex Quenching Mechanism**
Kazuhiko Mizuno,* Toshiyuki Tamai, Toshinori
Nishiyama, Kyoko Tani, Mayumi Sawasaki, and
Yoshio Otsuji
Photochemical polar addition of nucleophiles to alkenes can
be achieved by photoinduced electron transfer.['-"] This photoreaction often proceeds via radical cations of alkenes. which
are generated by photoinduced electron transfer from the alkene
to an electron acceptor; this reaction is generally very efficient
in polar media such as acetonitrile. Recently. we found that the
efficiency of the photoaddition of alcohols to arylalkenes sensitized by 9,lO-anthracenedicarbonitrileA depends markedly o n
the structure of the alkenes and the nature of the solvents.[s1The
photoaddition of methanol to 1.1-diphenylpropene occurs more
efficiently in less polar aromatic solvents such as benzene and
toluene than in acetonitrile. We now report the regio- and
stereoselective intramolecular photoaddition of o.w-diphenyl(w-1)-alkenols in the presence of A."] One step in this photoreaction is the quenching of the A -arylalkene exciplex by the
terminal OH group present in the alkenol.
Irradiation of a solution of 6,6-diphenyl-5-hexenol ( 1 c.
0.2 mmol) and a catalytic amount of A (0.04 mmol) in benzene
through an aqueous CuS0,-NH, filter solution ( j . > 400 nm)
gave 2-(diphenylmethy1)tetrahydropyran(2c) in 63 % yield (isolated product).[*] The intramolecular photocylization of 1 c occurred efficiently in aromatic solvents such as benzene and
[*I
[**I
Dr. K. Mimno. T. Nishiyama. K . Tmi, M. Sawasaki. Prof. Dr. Y.Otsuji
Department of Applied Chemistry. College of Engincering
University of Osaka Prefecture. Sakai. Osaka 593 (Japan)
Dr. T. Tdmal
Osaka Municipal Technical Research Institute. 1-6-50
Morinomiya, Joto-ku. Osaka 536 (Japan)
This work was supported in part by a Grant-in-Aid for Scientific Reseiirch
from the Ministry of Education. Science and Culture of Japan We thank Dr.
Y. Masdki, Dr. C. Pac. and Prof. S. Yanagida, Osaka Univcrsity. for mcasurements of fluorescence lifetimes of 9.10-ant11racenedic;trbonitrile.
COMMUNICATIONS
toluene and in halogenated solvents such as dichloromethane
but less efficiently in acetonitrile. propionitrile, and ethyl acetate.I91
The photoreactions of 1 b and I d under similar conditions
gave the corresponding cyclized products 2 b and 2d in good
yields. In contrast 1 a and 1 e -f. which have shorter or longer
methylene chains between the carbon -carbon double bond and
the OH group. did not give any cyclized products. In the
photoreactions of more flexible alkenes 3a-c, only 3 a afforded
the 1.4-dioxane 4 a in low yield."01 The photocyclization of 3substituted 6,6-diphenyl-5-hexenols Sa-c[' in benzene was
Ph,C=CH( CH2),,0H
la-f
"'
a : n=2, b : n=3. c : n d .
d : n=5. e : n=6, f : n=IO
Ph2C=CHCH2(OCH2CH,),OH
n=2,6,10
Table 1 . Stern Volmer constants for the lluorescence quenching of A in wtious
solvents and oxidation potentials of arylalkenes and other compounds.
la
Ib
1.14
IC
Id
le
If
I?,
3a
3b
3c
8a
8b
1.16
115
1.16
O
n=3,4,5
d
2b-d
2b: 68%. Zc: 6390, 2d: 60%
hc6H6
vlA
3a-c
-
110
156
I22
153
1 06
171
161
34
6
27
96
5
6
41
1.13
9
P h 2 c H n ~ ~ ) "
6
43
24
15
17
8
30
0 97
1.18
1.06
1 .(I 1
I .07
83
148
206
134
I 6X
I Oh
27
49
[a] Oxidation potentials (V v h . Ag:AgCIO,) were determined by cyclic voltammetry: Pt electrode. Bu,NCIO+(O.l M) in CH,CN. [b] Stern-Volrner constiinis lor the
fluorescence quenching o f A In three solvents. [A] = 1 x lo-" M. [c] In C,H, in the
presence of C H ,OH (1 M )
ph2cHil>)
and the ether 1 g. Furthermore, weak emissions from the A/Sa, b
exciplexes and the A/1 g exciplex were observed in benzene at
longer wavelengths than the emission from
4a.c
a : n=l, b : n=2, c : n=3
4a: 22%. 4b: trace, 4c: 1%
stereoselective and gave the cis and truiis 4-substituted 2(diphenylmethy1)tetrahydropyrans 6 a-c and 7 a-c, respectively. in about a 4: 1 ratio.[" The cislrrrins isomer ratios were little
affected by the reaction temperature, solvent, and substituents."'] The quantum yields for the formation of the cyclized products 2, 6, and 7 in benzene were five to ten times
higher than those in acetonitrile.
We propose the exciplex quenching mechanism shown in
Scheme 1 for the 9,lO-anthracenedicarbonitrile(A) sensitized
intramolecular photoaddition of 1 a-f. In benzene. a reversible
A
'A'
hv
+ D
'A'
___)
' [ A-D]'
exciplex
5a-c
6a - c
7a-c
Ph
a - R=CH3, b : R=t Bu. C : R=Ph
6a+7a:65%. 6b+7b:41%, 6c+7c:49%
Ph
The fluorescence of 9,10-anthracenedicarbonitrileA in acetonitrile was efficiently quenched by all the arylalkenes at nearly
diffusion-controlled rates; the rate constants for the fluorescence quenching were in the range of 3 . 3 10'~
1.3 x 10" M - ' s - ' ( T ~ =16.1
, ~ ~ns in
~ acetonitrile and 15.2 ns in
benzene). However, the Stern -Volmer constants K,, in benzene
were much smaller than those in acetonitrile (Table 1 ) . For 1 a,
1 f, and 1.1-diphenylpropene (Sa), the K,, values were much
smaller than that of 9-ethylidenefluorene (9),15. 3 1 although the
oxidation potentials of these alkenes are almost the same. The
fluorescence lifetime of A in benzene in the presence of methanol
(1 M) was almost the same as that in the absence of methanol
- 15.2 ns. T ' , , , ~ ~ ~ =
, 14.9
~ ~ , ns).
~ ~ ,However,
~ ~ ~
the K,,
value for 1f in the presence of methanol was four times greater
than that in neat benzene and almost the same as those for 1 b, c
+
/
R
1
x- + D'+
t
A + D
D=l,3,5
n=O,1.2
R = H. CH3, CHzCHzOH
X = CH,. 0, CHCH3. CH(t Bu). CHPh
Scheme 1. Exciplex quenching mechanism for the A-sensitized intramolecular photocyclization of c1.w-diphenyl-(w - 1 )-alkenols.
exciplex"'] is formed between the A in the excited singlet state
and the diphenylalkene moiety of the o-hydroxyalkene. This
exciplex is quenched by the O H group within the molecule.[". "] For 1 b-d, exciplex quenching leads to the five- to
seven-membered transition state structures that are favorable
for the formation of cyclized products. Exciplexes of the hydroxy ethers 3 b, c are not quenched by the OH group. but by the
oxygen atom of the oxyethylene group. Therefore, 3 b, c have
relatively large K,, values, although the photoreaction of 3b. c
33!Y4:2U20-2114
S IO.OU+ .23.'0
Angew. Ciimi. I n l . Ed. E q l . 1994. 33. N o . 20
COMMUNICATIONS
gives hardly any cyclized products.[' 81 The intramolecular photoreaction is extremely efficient compared to the intermolecular
photoaddition. In fact, the intramolecular photoaddition occurs
smoothly even at high concentrations of the alkenes ([lb] =
0.001 - 0.1 M).
Photoinduced electron transfer in acetonitrile is known to
occur rapidly to produce radical ions. However, in our system,
the radical cations, probably solvent-separated radical cations,
are less reactive toward alcohols. Solvent-separated radical ions
will be inactivated by rapid back electron-transfer.["] In fact,
the addition of Mg(CIO,), to the reaction systems suppresses
the formation of cyclized products.'"]
Received: May 5 , 1994 [ Z 6898 IE]
German veryion: Anpeir. Chcni. 1994. 106. 2203
Reviews: S. L. Mattes. S. Farid. Org. P/iorot./irm. 1983.6. 233; G. J. Kavarnos.
N . J. Turro. Ch~~t77.
Rev. 1986. X6, 401: J. Mattay. Angew. C/iw. 1987. Y9. 825:
A r i p ' i i Chcr7i. I i i r . Ed. Engi. 1987. 26. 825: F. D. Lewis in Plioroinihrced
troii T,.mis/cr., Purl C (Eds.: M. A. Fox, M. Chanonj. Elsevier. Amsterdam.
1988. p. 1 : J. Mattay. a ~ i ~ n r h c . ~1989.
i s , 233: K. Mizuno. Y Otsuji, Zip. Cirrr.
Chiw1. 1994. 169. 301.
R. A. Neunteufel. D. R. Arnold. J. Am. Chrm. SIC.1973, 95. 40x0: Y Shigemitsu. D. R. Arnold. J. Chrni. So<. Chern ('omniun. 1975. 407: A. .I Maroulis, Y
Shipemitsu. D. R. Arnold. J. A m . Clwrn. Soc. 1978, 100, 535; A. J. Maroiilis,
D. R . Arnold. .S,~~ri/hrsrs1979, 819; D. R. Arnold. X. Du. J. An?. Chem. SOL..
1989. 111. 7666. D. R . Arnold, X. Du. K . M. Henseleit. Can. 1 Chcwi~ 1991.69.
X39: K . Mcmahon. D. R. Arnold. h i d . 1993. 71, 450.
T. M;ijiina. c'. Pnc. H. Sakurai. J. Arn. C h m Sot.. 1981. 103, 4499.
F.D Le%is. R. J. DeVoe. D. B. MacBlane, J. Orx. Chmm. 1982.47. 1392: P. G.
Gassnian. K. D. Olson. Trrmh~dronLett. 1983. 24, 19; P. G. Gassman. K. J.
Bott"ff, rhid 1987, X . 5449: S. L. Mattes. S. Farid. J. Ani. Chcw7 Sot.. 1986.
107. 1426; 7 Hirano. S. Shiina. M. Ohashi, J. U w i f i . Sot.. Chrm. Cofsrrntrtz.
1992. 1544: Y. Inoue, T. Okano. N . Yamasaki. A. Tai. ihid. 1993, 71X
K. Mizuno. 1. Nakanishi. N . Ichinose. Y. Otsuji, Clzeni. Lerf. 1989, 1095.
E D. Lewis. G. D. Reddy. S. Schneider. M. Gahr. J. Awl. C h m . S(JC.1989. 1 I / ,
6465. h i d . 1991. 113. 3498. F. D. Lewis. G. D. Reddy, E,trahcdrori Lc,tr. 1992,
33. 4249: A . Sugimoto. R. Hiraoka. H. Inoue, T. Ad;ichi. J. Chon. Sot.. Perkin.
f i u i i \ . 1. 1992. 15S9: A . Sugimoto. R. Hiraoka. N . Fnkuda. H. Kosaku. H.
Inoue. diid 1992. 2871.
This work H R S presented in part at the United StatesIJapan seminar. "New
Aypects of Molecular Photochemistry in Photoconversion", Tsukuba. Japan.
April 13 17. 1992.
The qcliied products were characterized by their 'H NMR, "C NMR. and
two-dimenaional COSY and NOESY spectra. 2c: 'H N M R (270 MHz,
CDCI,): ii = 1.34-1.33 (m. 1 H: 3eq-H). 1.40-1.58 (m. 4 H ; 4-H. 5-H). 1.761.79 (ni. 1 H : 3;ix-Hj. 3.38-3.47 (m, 1 H : 6ax-H). 3.88 (d, J = 9.26 Hz. 1 H .
7-H). 3.95-3.96 (m, I H ; 6eq-H). 4.00-4.02 (m. 1H. 2-H). 7 13-7.35 (m.
1 0 H ) . I R ( K B r ) : i ' = 1091 cm ' : M S ( 7 0 e V ) : m / ; : E 5 2 ( i M i ) . - 6 c : ' H N M R
(170 MHz.CDCI,):d = 1.39-1.53(m. 1 H;3eq-H). 1.67-1.84(m,3H:3ax-H.
5-H), 2.70-2.82 (m. 1 H : 4-Hj. 3.51 3.73 (m. 1 H: heq-H). 3.95 (d.
= 9.40 Hz. 1 H: 7-H). 4.09-4.16 (m, 2 H : 2-H, hiix-H). 7.1 3 7.35 (m. 1 5 H):
IR (KBrj: I' = 1100. 1042 cm I : MS (70 eV): High-resoluuon MS of M ' :
328.1936 (calcd C,,H,,O: 328.1X27). - 7c: ' H N M R (270 MHz. CDCI,):
B = 1.68-1.7X(m, 1H;3eq-H),1.87-1.98(m.3H:3ax-H.5-H).3.13
3.25(m,
1 H : 4-H), 3.63 ~ 3 . 7 1(m. I H: heq-H). 3.78-3.XX (in. I H : hax-Hj. 4.3X id,
J = 9 . 4 0 H ~ ,I H ; 7-H). 4.55-4.63 (m. I H : 2-H). 7.14 7.36 (m. 15H): IR
(KBr). v = 1125. 1084cm I: MS (70eV): High-resolution MS or iM"
328.1817 (calcd C,,H,,O. 318.1827).
[9] Relative quantum yields for the formation of 2c in various solvent\: 0 70
(C,H,j. 0.72 (PhMe). 0.22 (MeC0,Et). 1.0 (CH,CI,). 0 07 ( E t C N J , 0.06
(MeCN).
[lo] The phcnanthrene- 1,4-benienedicarbonitrilesensitized photoreaction o f 3 a
:
f o r 4 a . 6 % for4h.Y% for4c):I'heuc
cinacetonitrilegave4a ~ ( y i e l d s 13%
reactions probably proceed via the riidical cations of 3 a c [?I.
[11] 5 c : ' H N M R (270 MHz. CDCI,): d = 1.76- 1.98(m. 2H). 2.39 2.47 (in. 2 H ) .
2.X0-2.90(m, I H j , 3 . 3 7 ~ 3 . 5 2 ( m . 2 H j , 5 . 9 6 ( t , J = 7 . 4 5 H z .IH).7.(11--7.37
(m. 1 5 H): IR (film): 1' = 3400 cm I : MS (70 eV): high-resolution MS of M :
328.1842 (calcd CLIHIaO: 328.3827).
[12] Product riltioa of 6a-c;7a-c in different solvents: 6a.'7a = X3.17 (CC14).
82.18 (C,,H6), X0:20 (CH,CI,j. 80:?0 (C,H,Br). 84.26 (MeCN): 6b:
7 b = 72:28 (CCI,), 71:29 (C,H,j, 75:25 (CH,CI,). X I : l 9 (EtBr). 70:21
(MeCN);6c:7c = >Y8 >2(CCI,), 83:17 (C,H,,j. X0:20 (CH:C12). 78:22(EtBr), 83: 17 (MeCN). Ruiios at different temperatures: 6a;7a = 79 :21 ( 20 C.
CH,CI,j, 73:27 (50 C. CH,CI,). 72:28 (70 C , CH,CII). X5.15 (-60 C'.
C,H,Mej, 7X:22 (10 C, C,H,Me). 73:27 (80 C. C,H,Me). 72:78 (150 (..
C,H,Me).
1131 The fluorescence of 'A* w a s efficiently quenched by 9. probably a\ ii rrcult of
the sandwich-type n-n interaction.
[I41 The exciplex emiysions were quenched by adding methanol to the benzcne
solutions.
[IS] Although l a , I f , a n d 8 a haveoxid.ationpotentialssimilartothoscollb cand
9. their K,, values are relatively small (Table I ) . The formation of reversible
exciplexes i s postulated based o n these results. See D. A. 1~abi;inca.G. N .
Taylor. G. S. Hammond, J. A m Chrm. Soc. 1972, Y4. 3679.
(16) R. A. Caldwell. L. Smith. J. AIW. Chrvn. Sor. 1974, Y6. 2994: D. freed. R. A.
Caldwell. ihrrl. 1974. 96. 7369: D. Creed. R. A. Caldwell. H. Ohta. D. C.
DeMacro. ihrd. 1977. W . 277: C. Pac. H. Sakurai. Cher7i. Lrfr 1976. 1067: T.
Majima. C. Pac. H. Sakurai, Bull Chiwi. Sot.. J / m 1978. 51. 181 1.
[I71 The A-sensitized photoaddition of methanol to 1.1-diphenylethene (DPE) in
acetonitrile is inefficient [ S ] : the phenanthrene I .4-benzenedicarbonitrilescnsitired photoaddition in acetonitrile is efficient [ 3 ] . The n complex [(phcnanthrene-DPEj"]. which has a longer lifetime than the solvent-separated radical cation of DPE, has been propo5ed as a key ititermediate hy Pac ct al. [3].
I n the A-sensitixed intramolecular photocyclimtion in benzenr. the solvent
may act a? a n donor to stabilize the radical cation of ~u-hydroxy;ilkencs.K.
Mizuno, K . Nakanishi, Y Otsuji. Chern. Lerr. 1988, 1833. See also ref. [IY].
[IX] It is notable here that the large K,, valuesdo not necessarily l e d to the efficient
formalion of the cyclired products. For 3a. an intramolecular hydrogen bond
may be formed between the OH groups and the oxygen atom uf the
oxyethylene group. and hence the exciplex is quenched less efficiently.
[19] K. Mizuno. N. Ichinose. Y Otsuji, J Ur~q.Chiwi. 1992. .i7. 1x5s a n d reference\
cited therein.
J
+
Документ
Категория
Без категории
Просмотров
0
Размер файла
357 Кб
Теги
quenching, intramolecular, ols, mechanism, exciplex, alkene, photocyclization, diphenyl
1/--страниц
Пожаловаться на содержимое документа