Photochemistry of 6-Substituted Cyclohexenones
P h otolysis of 2f in C6D6. A solution of 6 mg of 2f in 1.0
mL of C6D6 was photolyzed following the typical procedure.
The reaction led to mixtures of endo-3-benzoyloxy-trans-5,6-
diphenylbicyclo[3.1.0]hexan-2-one (5f) as white crystals and
exo-3-benzoyloxy-tra ns-5,6-diphenylbicyclo[3.1.0]hexan-2-
one (6f) as white crystals.
Ir r a d ia tion s ver su s Tim e for 2f. With times of 20, 60,
120, and 180 min, the conversions were 18%, 54%, 83%, and
97%, respectively. The ratios of endo to exo product were >20,
6.7, 4.2, and 3.6, respectively.
P h otolysis of 2i in C6D6. A solution of 20 mg of 2i in 1.0
mL of C6D6 was photolyzed following the typical procedure.
The reaction was monitored by NMR in chloroform-d (δ-
(HCCN) ) 3.40 ppm (endo) and 2.20 ppm (exo)) and led to
endo-3-cyano-trans-5,6-diphenylbicyclo[3.1.0]hexan-2-one (5i)
and exo-3-cyano-trans-5,6-diphenylbicyclo[3.1.0]hexan-2-one
(6i).
P h otolysis ver su s Con ver sion of 2i. After times of 20,
40, and 100 min, the conversions were 22%, 33%, and 73%
and the ratios of 5i to 6i were 1.44, 1.16, and 0.67, respectively.
The reaction mixture was chromatographed on a silica gel
column slurry packed and eluted with 15% ether in hexane to
give 6 mg (30%) of the initial 2i and 12 mg (60%) of 6i as white
Data for compound 5f: mp 138-140 °C; 1H NMR (CDCl3) δ
7.6-7.2 (m, 15 H), 5.45 (ddd, 1 H), 3.25 (d, 1 H), 3.10 (ddd, 1
H), 2.90 (dd, 1 H), 2.30 (dd, 1 H); HRMS m/ z 391.1329
(391.1310, calcd for C25H20O3Na, M + Na+). Data for compound
1
crystals: mp 143-144 °C; H NMR (CDCl3) δ 7.5-7.3 (m, 10
1
6f: mp 60-62 °C; H NMR (CDCl3) δ 7.95 (m, 2 H) 7.6-7.2
H), 3.30 (d, 1 H), 2.9-2.6 (m, 3 H), 2.19 (dd, 1 H); HRMS m/z
296.1041 (296.1051, calcd for C19H15NONa, M + Na+).
Kin etic Ep im er iza tion of 6i. To a solution of 4 mg of 6i
in 2.0 mL of methanol were added 2.0 mL of water and 20 mg
of potassium hydroxide. The clear yellow solution was kept
for 5 min at 25 °C, diluted with 3.0 mL of water, acidified with
1 N HCl, and ether extracted (3 × 5 mL). The extract was
dried (Na2SO4) and concentrated to give 3 mg of a 4:1 mixture
of 5i and 6i. Data for the mixture of 5i and 6i: 1H NMR
(CDCl3) δ 7.5-7.3 (m, 10 H), 3.43 (dd, 0.8 H, 5i), 3.28 (m, 1 H,
5i + 6i), 3.0-2.6 (m, 3 H, 5i + 6i), 2.20 (dd, 0.2 H, 6i).
Attem p ted P h otolysis of 2i in th e Solid Sta te. A 21 mg
(0.08 mmol) portion of crystalline 2i was photolyzed for 11.5
h following the typical procedure. After the workup only 20
mg (95%) of the initial cyanide 2i was isolated.
(m, 13 H), 4.10 (dd, 1 H), 3.30 (d, 1 H), 3.00 (dd, 1 H), 2.80 (d,
1 H), 2.55 (dd, 1 H); HRMS m/z 391.1311 (391.1310, calcd for
C
25H20O3Na, M + Na+).
P h otolysis of 2f in CD3OD. A solution of 10 mg of 2f was
photolyzed for 1 h following the typical procedure. By NMR
analysis, the reaction mixture contained 5f (48%), 6f (19%),
and cis-4,5-diphenyl-6-benzoyloxycyclohex-2-en-1-one (7f) (6%).
The conversion was 73%. The reaction mixture was chromato-
graphed on a silica gel column (HPLC), eluted with 15% ether
in hexane, to give 4 mg (40%) of 5f, 1 mg (10%) of 6f, and 0.5
mg (5%) of 7f as white crystals: mp 55-57 °C); 1H NMR
(CDCl3) δ 8.05 (m, 2 H), 7.6-7.0 (m, 13 H), 6.56 (d, J ) 2.5
Hz, 1 H), 5.86 (dd, J ) 14.0, 5.0 Hz, 1 H), 4.58 (ddd, 11.0, 5.0,
2.5 Hz, 1 H), 2.81 (ddd, J ) 14.0, 5.0, 5.0 Hz, 1 H), 2.46 (ddd,
J ) 14.0, 14.0, 11.0 Hz, 1 H); HRMS m/z 391.1320 (391.1310,
calcd for C25H20O3Na, M + Na+).
P h otolysis of 2f in th e Cr ysta llin e Sta te. A 8.0 mg
portion of crystalline 2f was photolyzed for 7 h following the
typical procedure. The reaction led to a mixture of the initial
2f (54%), 5f (14%), and 6f (32%).
P h otolysis of 2g in CD3OD. A solution of 5.0 mg of 2g in
1.0 mL of CD3OD was photolyzed following the typical
procedure. The reaction was monitored by NMR (δ(HCOPh-
thal) ) 5.40 ppm (endo) and 3.95 ppm (exo)) and led to
mixtures of endo-3-phthaloyloxy-trans-5,6-diphenylbicyclo-
[3.1.0]hexan-2-one (5g), exo-3-phthaloyloxy-trans-5,6-diphe-
nylbicyclo[3.1.0]hexan-2-one (6g), and 6-phthaloyloxy-4,5-
diphenylcyclohex-2-en-1-one 7g or 8g.
P h otolysis ver su s Con ver sion for 2g. With times of 45
and 100 min, the conversions were 23% and 39%, respectively.
The ratios of 5g to 6g were 2.3 and 3.5, and the unsaturated
product yields were 4% and 11%, respectively.
Attem p ted P h otolysis of 2g in th e Solid Sta te. An 11
mg portion of crystalline 2g was photolyzed for 11.0 h following
the typical procedure. After the workup only 10 mg (91%) of
the initial 2g was isolated.
P h otolysis of 2h in C6D6. A solution of 20 mg of 2h in 1.0
mL of C6D6 was photolyzed following the typical procedure.
The reaction led to endo-3-phenylcarbamato-trans-5,6-diphe-
nylbicyclo[3.1.0]hexan-2-one (5h ) and exo-3-phenylcarbamato-
trans-5,6-diphenylbicyclo[3.1.0]hexan-2-one (6h ).
P h otolysis ver su s Con ver sion for 2h . After 15 and 45
min, the conversions were 23% and 50% and the ratios of 5h
to 6h were 3.5 and 3.2, respectively.
Attem p ted P h otolysis of 2i in CD3OD. A solution of 4
mg (0.080 mmol) of crystalline 2i in 1.0 mL of CD3OD was
irradiated following the typical procedure. Only the starting
cyanide 2i, deuterated at the R-position to the cyano group,
was isolated (4 mg, 100%).
P h otolysis of 2j in C6D6. A solution of 5.0 mg of 2j in 1.0
mL of C6D6 was photolyzed following the typical procedure.
The reaction led to endo-3-methyl-exo-3-cyano-trans-5,6-
diphenylbicyclo[3.1.0]hexan-2-one (5j) and exo-3-methyl-endo-
3-cyano-trans-5,6-diphenylbicyclo[3.1.0]hexan-2-one (6j).
P h otolysis ver su s Con ver sion for 2j. After 10 and 40
min, the conversions were 57% and 100%, respectively. The
ratios of 5j to 6j were 3.4 and 2.8, respectively.
The reaction mixture was chromatographed on a silica gel
column (HPLC), eluted with 33% chloroform in hexane, to give
5j as white crystals and 6j as white crystals. Data for
compound 5j: mp 94-95 °C (hexanes-ether); 1H NMR (CDCl3)
δ 7.5-7.2 (m, 10 H), 3.30 (d, 1 H), 3.15 (dd) + 2.96 (d), (2 H),
2.40 (d, 1 H), 0.50 (s, 3 H); HRMS m/z 310.1214 (310.1208,
calcd for C20H17NONa, M + Na+). Data for compound 6j: mp
136-137 °C (hexanes-ether); 1H NMR (CDCl3) δ 7.5-7.2 (m,
10 H), 3.35 (d, 1 H), 2.97 (d) + 2.90 (d), (2 H), 2.40 (dd, 1 H),
1.55 (s, 3 H); HRMS m/ z 310.1200 (310.1208, calcd for C20H17
-
NONa, M + Na+).
P h otolysis of 2j in CD3OD. A solution of 33 mg of 2j in
2.0 mL of CD3OD was photolyzed for 100 min following the
typical procedure. The reaction mixture was chromatographed
on a silica gel column slurry packed and eluted with 20% ether
in hexane to give 7 mg (21%) of the starting 2j, 12 mg (36%)
of 5j, 10 mg (30%) of 6j, 2 mg (6%) of cis-6-cyano-trans-6-
methyl-3,4-diphenylcyclohex-2-en-1-one (7j), and 2 mg (6%) of
trans-6-cyano-6-cis-methyl-3,4-diphenylcyclohex-2-en-1-one (8j).
Data for compound 7j: 1H NMR (CDCl3) δ 7.3-7.0 (m, 10 H),
6.57 (d, J ) 2.5 Hz, 1 H), 4.68 (ddd, J ) 11.0, 5.0, 2.5 Hz, 1
H), 2.72 (dd, 15.0, 5.0 Hz, 1 H), 2.15 (dd, J ) 15.0, 11.0 Hz, 1
H), 1.55 (s, 3 H); HRMS m/z 310.1214 (310.1208, calcd for
The reaction mixture was chromatographed on a silica gel
column (HPLC), eluted with 33% hexane in CH2Cl2, to give 8
mg (40%) of starting 2h , 1 mg (5%, purity ca. 90%) of 6h , and
5 mg (25%) of 5h as a clear oil: 1H NMR (CDCl3) δ 7.5-6.9
(m, 15 H), 5.80 (br s, 1 H), 5.05 (m, 1 H), 3.25 (d, 1 H), 3.00
(ddd, 1 H), 2.85 (dd, 1 H), 2.30 (dd, 1 H). HRMS m/z 406.1418
(406.1419, calcd for C25H21NO3Na, M + Na+) Data for com-
pound 6h : 1H NMR (CDCl3) δ 7.5-7.2 (m), 6.65 (br s, NH),
3.90 (dd), 3.30 (d), 3.00 (dd), 2.80 (d), 2.50 (d).
Attem p ted P h otolysis of 2h in th e Solid Sta te. A 21
mg portion of crystalline 2h was photolyzed for 10.0 h following
the typical procedure. After the workup only 20 mg (95%) of
the initial 2h was isolated.
C
20H17NONa, M + Na+). Data for compound 8j: 1H NMR
(CDCl3) δ 7.3-7.0 (m, 10 H), 6.60 (d, J ) 1.8 Hz, 1 H), 4.40
(m, 1 H), 2.7-2.6 (m, 2 H), 1.73 (s, 3 H); 1H NMR (C6D6) δ
7.0-6.6 (m, 10 H), 6.32 (d, J ) 1.8 Hz, 1 H), 3.67 (ddd, J )
9.0, 6.0, 1.8 Hz, 1 H), 2.13 (dd, 14.5, 9.0 Hz, 1 H), 1.86 (dd, J
) 14.5, 6.0 Hz, 1 H), 1.20 (s, 3 H); HRMS m/z 310.1205
(310.1208, calcd for C20H17NONa, M + Na+).
J . Org. Chem, Vol. 68, No. 2, 2003 291