1
462 J. Am. Chem. Soc., Vol. 118, No. 6, 1996
,4-Pyridinediylbisfulvene 11f. From 1.00 g of 2,4-diacetylpyridine
West et al.
2
added. After 30 min, another 0.43 g of DMAD was added. After 30
min, the solution was rotoevaporated, and the residue was chromato-
graphed (1:5 hexanes-ethyl acetate), providing 0.466 g (70%) of the
unreduced bis-adduct 10u as a foamy yellow solid: 1H NMR δ 8.30
(dd, J ) 6.5, 2.1 Hz, 2H), 7.33 (br s, 1H), 6.80 (br s, 4H), 5.9-5.0 (br
m, 4H), 3.81 (s, 6H), 3.74 (s, 6H), 2.06 (s, 6H). A 0.453 g portion of
10u was reduced as described above, providing 0.436 g (96%; 67%
for two steps) of 10r as a foamy yellow solid: 1H NMR δ 8.36 (dd, J
) 7.1, 2.0 Hz, 2H), 7.41 (br s, 1H), 5.2-4.5 (br m, 4H), 3.86 (s, 6H),
3.74 (s. 6H), 2.14 (s, 6H), 2.2-1.7 (2 br s, 8H); 13C NMR δ 157 (br),
147.36, 137.64, 136.22, 133.59, 121.44, 59.4, 53.4 (br) 27.3 (v br),
(6.13 mmol), 13 mL of methanol, 2.6 mL of cyclopentadiene (31.5
mmol, 2.6 equiv/equiv of ketone), and 5.6 mL of pyrrolidine (61.9
mmol, 5.1 equiv/equiv of ketone), stirred for 17 h, was obtained a dark
brown solution. This was quenched with 3.9 mL of acetic acid (68.1
mmol, 5.6 equiv/equiv of ketone) and rotoevaporated to remove
methanol. The residue was treated with 10 mL each of water and
saturated aqueous NaCl and then extracted with 6 × 20 mL of ether.
The ether extracts were combined, dried (MgSO
4
), and filtered. The
filtrate was rotoevaporated and chromatographed (8:1 hexanes-ethyl
acetate), affording 0.205 g (13%) of an orange oil. Preparation with
CpMgBr gave only a trace of bisfulvene: H NMR δ 8.67 (dd, J )
1
+
+
20.3 (br); FAB-MS m/z (MH ) 556. HRMS for ([M + H] )
, calcd 556.2407, found 556.2388.
2,4-Pyridinebiscarbamate 11r. From 0.200 g of bisfulvene 11f,
5
.0, 0.6 Hz, 1H), 7.38 (dd, J ) 1.7, 0.6 Hz, 1H), 7.21 (dd, J ) 5.0, 1.7
27 34 5 8
C H N O
Hz, 1H), 6.65 (dt, J ) 5.3, 1.6 Hz, 1H), 6.58 (m, 3H), 6.49 (dm, J )
5
1
1
1
2
2
.3 Hz, 2H), 6.27 (dt, J ) 5.3, 1.7 Hz, 1H), 6.12 (dt, J ) 5.3, 1.7 Hz,
H), 2.63 (s, 3H), 2.50 (s, 3H); C NMR δ 158.89, 149.21, 148.70,
chromatographed using 1:2 hexanes-ethyl acetate, was isolated 0.263
g (61%) of a foamy pale yellow-orange solid: 1H NMR δ 8.58 (d, J )
5.1 Hz, 1H), 7.04 (br m, 2H), 5.21-4.48 (br m, 4H), 3.82 (s, 6H),
3.75 (s, 6H), 2.20 and 2.14 and 2.07 (each s, tot 6H), 1.98 (br m, 8H);
C NMR δ 158.48, 157.42, 149.06, 148.78, 138.36, 137.65, 123.64,
122.80, 120.99, 120.84, 59.37, 53.33, 26.57, 20.8, 19.7, 18.6; DEI-MS
1
3
47.00, 145.10, 144.47, 144.43, 132.99, 132.71, 132.44, 132.35, 124.81,
22.73, 122.57, 122.50, 121.56, 120.84, 21.74, 20.72; MS m/z (M )
59 (100), 244 (75); HRMS for [M-H] C19
58.1297; UV (CH
•
+
+
13
H16N, calcd 258.1283, found
2
Cl
2
) λmax 292 nm.
•+
Preparation of Carbamates by DMAD Addition to Fulvenes:
33 5 8
m/z (M ) 555 (33), 409 (100), 408 (45); HRMS for C27H N O , calcd
2
-Pyridinecarbamate 18r. Fulvene 18f (0.631 g, 3.73 mmol) was
555.2329, found 555.2328.
dissolved in 20 mL of CH
mmol, 1.11 equiv) in 5 mL of CH
2
Cl
2
under argon. DMAD (0.607 g, 4.15
Cl was added. After 2 h, the
Representative Preparation of Diazenes: 2-Pyridinediazene 18-
(N ). Carbamate 18r (0.225 g, 0.747 mmol) and powdered 87% KOH
2
2
2
solution was cooled in an ice-water bath and 2.17 g of PADC (11.2
(686 mg, 15 equiv) were degassed three times on the vacuum line and
purged for 10 min with argon. Isopropyl alcohol (20 mL, degassed
by 30 min of argon bubbling) was added via cannula, and the mixture
was stirred and heated to reflux for 90 min. The light brown mixture
mmol, 3.0 equiv) was added. A solution of 1.57 mL of acetic acid
(
27.4 mmol, 7.3 equiv) in 3 mL of CH
0 min. The mixture was stirred overnight as the ice bath melted. The
mixture was quenched with 20 mL of water, and the layers were shaken
and separated. The aqueous layer was extracted with 25 mL of CH
Cl . The organic extracts were combined, dried (K CO ), and filtered.
2 2
Cl was added dropwise over
2
was cooled to room temperature, and 0.89 g of NaHCO (15 equiv)
3
2
-
was added. The mixture was stirred for 1 h at room temperature, and
the solvent was pumped off overnight. The light brown residue was
2
2
3
The filtrate was rotoevaporated and chromatographed (2:1 hexanes-
partitioned between 25 mL each of water and CH Cl2 with gentle
2
1
ethyl acetate), providing 0.914 g of a brown foam. In this case, H
shaking, and the layers were separated. The aqueous layer was
extracted with 25 mL of CH Cl . The organic layers were combined,
NMR indicated incomplete reduction, so the material was resubjected
to the reduction conditions above, and the filtrate was rotoevaporated
2
2
dried (K CO ), filtered, and cooled in an ice-water bath. Nickel
2
3
1
to provide 0.856 g (72%) of a foamy brown solid: H NMR δ 8.59
peroxide (NiO , 1.21 g) was added, and the mixture was stirred in the
x
(
dd, J ) 4.8, 0.6 Hz, 1H), 7.69 (dd, J ) 7.6, 1.3 Hz, 1H), 7.29 (br s,
dark. After 1 h the mixture was filtered through Celite and rotoevapo-
rated, providing 111 mg (75%) of a pale yellow film, dried while being
cooled in an ice-water bath: 1H NMR δ 8.54 (d, J ) 4.8 Hz, 1H),
8.40 (s, 1H), 7.47 (d, J ) 7.9 Hz, 1H), 7.29 (dd, J ) 7.9, 4.8 Hz, 1H),
5.53 (s, 1H), 5.23 (s, 1H), 2.03 (s, 3H), 1.79 (m, 2H), 1.20 (m, 2H);
1
6
1
5
H), 7.20 (ddd, J ) 7.6, 4.8, 0.6 Hz, 1H), 5.06 (br m, 2H), 3.79 (br m,
13
H), 2.19 (s, 3H), 1.98 (br m, 4H); C NMR δ 158.05, 157.3 (w br),
48.81, 137.68, 136.05, 123.90, 122.10, 121.95, 59.31 (br m), 53.23,
•
+
2.96, 27.8 (br m), 26.5 (br m), 18.29; MS m/z (M ) 317 (8), 171
, calcd 317.1376, found
13
(70), 170 (100); HRMS for C16
H
19
N
3
O
4
C NMR δ 148.23, 148.07, 143.26, 135.86, 134.29, 122.79, 121.28,
74.03, 73.94, 21.05, 20.79, 19.32; UV (CH Cl ) λ ∼266 (sh), 330,
3
17.1362.
2
2
max
3
-Pyridinecarbamate 16r. From 0.414 g of fulvene 16f as above,
338 nm.
chromatographed using 1:2 hexanes-ethyl acetate, was isolated 0.601
3-Pyridinediazene 16(N ). From 0.222 g of carbamate 16r was
2
1
isolated 104 mg (75%) of an off-white solid: 1H NMR δ 8.58 (dm, J
) 4.8 Hz, 1H), 7.66 (td, J ) 7.7, 1.8 Hz, 1H), 7.17 (m, 2H), 5.63 (d,
J ) 2.4 Hz, 1H), 5.53 (d, J ) 2.4 Hz, 1H), 2.08 (s, 3H), 1.82 (m, 2H),
g (77%) of a sticky slightly foamy pale yellow solid: H NMR δ 8.55
(
d, J ) 4.7 Hz, 1H), 8.48 (s, 1H), 7.60 (d, J ) 7.7 Hz, 1H), 7.34 (dd,
J ) 7.7, 4.7 Hz, 1H), 5.07-4.57 (br m, 2H), 3.81 (s, 3H), 3.74 (s,
3
1
1
3
13
H), 2.15 (s, 3H), 1.93 (br m, 4H); C NMR δ 158.2, 156.9, 147.86,
1.18 (m, 2H); C NMR δ 157.76, 148.79, 144.66, 135.90, 123.66,
47.55, 136.80, 136.16, 134.62, 122.84, 121.32, 58.83, 52.78, 26.46
121.90, 121.79, 74.53, 74.18, 21.00, 20.73, 17.83; UV (CH Cl ) λ
2
2
max
•
+
(
(
br m), 19.58 (br); MS m/z (M ) 317 (65), 230 (54), 171 (55), 170
100); HRMS for C16 , calcd 317.1376, found 317.1378.
-Pyridinecarbamate 17r. From 0.424 g of fulvene 17f as above,
270, 332, 338 nm.
19 3 4
H N O
4
-Pyridinediazene 17(N ). From 0.250 g of carbamate 17r was
2
1
4
isolated 89 mg (57%) of a pale yellow oil: H NMR δ 8.58 (d, J )
chromatographed using ethyl acetate, was isolated 0.752 g (94%) of a
6.0 Hz, 2H), 7.05 (d, J ) 6.0 Hz, 2H), 5.52 (d, J ) 2.2 Hz, 1H), 5.26
1
13
foamy off-white solid: H NMR δ 8.60 (d, J ) 4.8 Hz, 2H), 7.16 (d,
(d, J ) 2.2 Hz, 1H), 2.02 (s, 3H), 1.79 (m, 2H), 1.19 (m, 2H);
C
J ) 4.8 Hz, 2H), 5.06-4.59 (br m, 2H), 3.82 (s, 3H), 3.74 (s, 3H),
NMR δ 149.57, 147.97, 144.03, 122.43, 122.06, 74.12, 73.94, 21.04,
20.80, 18.89; UV (CH Cl ) λ 338 (sh) nm.
1
3
2
1
(
.12 (s, 3H), 2.2-1.58 (br m, 4H); C NMR δ 149.33, 148.77, 137.62,
22.66, 122.34, 59.12 (br), 53.30 (br) 26.7 (br m), 19.61 (br); MS m/z
2
2
max
2 2
2,6-Pyridinebisdiazene 12(N ) . From 0.272 g of biscarbamate 12r
•+
M ) 317 (93), 289 (52), 230 (99), 186 (56), 170 (100), 49 (46); HRMS
for C16 , calcd 317.1376, found 317.1380.
,6-Pyridinebiscarbamate 12r. From 0.396 g of bisfulvene 12f,
was isolated a pale yellow film, which was chromatographed (2:3
19 3 4
H N O
hexanes-ethyl acetate), providing a pale yellow film: 1H NMR (300
2
MHz) δ 7.66 (t, J ) 7.8 Hz, 1H), 7.07 (dd, J ) 7.8 Hz, ∆δ ) 1.5 Hz),
5.65 (d, J ) 2.19 Hz) and 5.62 (d, J ) 2.21 Hz) and 5.55 (d, J ) 2.24
Hz) (∼1:1:2, tot 4H), 2.12 (d, ∆δ ) 1.38 Hz, 6H), 1.85 (m, 4H), 1.21
(m, 4H). The peaks between 5.65 and 5.55 ppm show further fine
splitting with J ∼ 0.6 Hz. The separation between the 5.65 and 5.62
chromatographed using 1:2 hexanes-ethyl acetate, was isolated 0.623
1
g (73%) of a foamy yellow-brown solid: H NMR δ 7.69 (br t, J )
7
.7 Hz, 1H), 7.21 (br s, 2H), 5.07 (br m, 4H), 3.80 (br s, 6H), 3.75 (br
1
3
s, 6H), 2.20 (2s, ∆δ ) 1.8 Hz, tot 6H), 1.98 (br m, 8H); C NMR δ
1
157.50 (m), 137.95, 136.70, 124.10, 120.98 (br), 59.62 (br), 53.24 (m),
ppm peaks is 10.3 Hz. H NMR (400 MHz) δ 7.63 (t, J ) 7.8 Hz,
•
+
2
6.56 (br m), 18.54 (br); DEI-MS m/z (M ) 555 (18), 409 (63), 321
1H), 7.04 (dd, J ) 7.8 Hz, ∆δ ) 2.3 Hz), 5.65 (d, J ) 2.34 Hz) and
5.62 (d, J ) 2.32 Hz) and 5.55 (d, J ) 2.32 Hz) (∼1:1:2, tot 4H), 2.08
(d, ∆δ ) 2.0 Hz, 6H), 1.85 (m, 4H), 1.22 (m, 4H). The peaks between
5.65 and 5.55 ppm show further fine splitting with J∼0.6 Hz. The
separation between the 5.65 and 5.62 ppm peaks is 14.2 Hz. Decou-
pling experiments were performed. Irradiating the 1.85 ppm peak
33 5 8
(18), 262 (38), 261 (21), 260 (28), 59 (100); HRMS for C27H N O ,
calcd 555.2329, found 555.2318.
3
,5-Pyridinebiscarbamate 10r. Bisfulvene 10f (0.310 g, 1.20
mmol) was dissolved in 10 mL of CH Cl under argon. DMAD (0.430
g, 2.90 mmol, 1.2 equiv/equiv of fulvene) in 5 mL of CH Cl was
2
2
2
2