REACTION OF METHYL DIAZOACETATE
107
The reaction of 2-(3-butenyl)-2-methyl-1,3-diox-
olane (VII) with N2CHCO2Me in the presence of
Rh2(OAc)4 leads to the formation of a mixture of dim-
ethyl esters of trans- and cis-2-[2-(2-methyl-1,3-diox-
olan-2-yl)ethyl]cyclopropanecarboxylic acids (VIII) in
a 3 : 2 ratio and 40% total yield.
At the same time, the reaction of 2-(3-butenyl)-2-
methyl-1,3-oxathiolane (IX) with N2CHCO2Me cata-
lyzed by Rh2(OAc)4 is accompanied by the insertion of
a methoxycarbonylmethylene fragment into a five-
membered ring resulting from the Stevens rearrange-
ment of the initially formed S-ylide to give selectively
methyl 2-(3-butenyl)-2-methyl-1,4-oxathiane-3-car-
boxylate (X) in 50% yield.
MeO2C
Me
Me
Rh2(OAc)4
+ N2CHCO2Me
O
O
CH2Cl2
O
O
(VII)
(VIII)
O
O
Rh2(OAc)4
S
S
+ N2CHCO2Me
CH2Cl2
CO2Me
Me
Me
(IX)
(X)
We obtained unexpected results for the reaction of oxazolidines (XI, XII) to form cinnamaldehyde and
hexen-2-one, respectively.
Thus, our study showed that the direction of the
reaction of the unsaturated compounds with
2-(trans-2-phenylethenyl)-3-ethyl-1,3-oxazolidine (XI)
and 2-(3-butenyl)-2-methyl-3-ethyl-1,3-oxazolidine (XII)
with N2CHCO2Me in the presence of Rh2(OAc)4. It was
found that Rh2(OAc)4 catalyzes the cleavage of initial N2CHCO2Me in the presence of Rh2(OAc)4 is deter-
Table 1. Yields and 1H NMR spectra for compounds IIIa, IIIb, IVa, Va, Vb, VIa, VIb, VIII, and X
Compound Yield, %
1H NMR spectrum (δ, ppm, J, Hz)
IIIa (X = O,
32
47
8
1.72 (d, 3 H, Me, 3J = 6.3); 3.86 (m, 2 H, H2C(5)); 3.95 (m, 2 H, H2C(6)); 3.83 (dd, 1 H, HC(3),
3J = 5.8, 3J = 8.8); 3.92 (s, 3 H, OMe); 4.15 (d, 1 H, HC(2), 3J = 5.8); 5.41 (dd, 1 H, HC(1'),
3J = 8.8, 3J = 15.7); 5.82 (dq, 1 H, HC(2'), 3J = 6.3, 3J = 15.7)
3.73 (s, 3 H, OMe); 3.88–3.96 (m, 4 H, H2C(5) and H2C(6)); 4.04 (d, 1 H, HC(2), 3J = 8.8);
4.25 (dd, 1 H, HC(3), 3J = 7.1, 3J = 8.8); 6.15 (dd, 1 H, HC(1'), 3J = 16.0, 3J = 7.1);
6.72 (d, 1 H, HC(2'), 3J = 16.0); 7.27–7.35 (m, 5 H, Ar)
1.68 (d, 3 H, Me, 3J = 6.1); 2.39 (m, 2 H, H2C(6)); 3.95 (m, 2 H, H2C(5)); 3.45 (d, 1 H, HC(2),
3J = 12.5); 3.71 (s, 3 H, OMe); 4.78 (dd, 1 H, HC(3), 3J = 12.5, 3J = 6.7); 5.51 (dk, 1 H, HC(2'),
3J = 6.1, 3J = 15.5); 5.72 (dd, 1 H, HC(1'), 3J = 6.7, 3J = 15.5)
R = Me)
IIIb (X = O,
R = Ph)
IVa (X = S,
R = Me)
Va (X = O,
55
23
8
1.02 (d, 3 H, Me, 3J = 7.2); 2.76–2.89 (ddq, 1 H, HC(6), 3J = 5.1, 3J = 7.2, 3J = 10.1); 3.70 (t, 2 H,
H2C(3), 3J = 7.1); 3.71 (s, 3 H, OMe); 4.36 (t, 2 H, H2C(2), 3J = 7.1); 4.54 (d, 1 H, HC(5),
3J = 10.1); 4.82 (dd, 1 H, HC(7), 3J = 5.1, 3J = 6.3); 5.79 (d, 1 H, HC(8), 3J = 6.3)
3.52 (t, 2 H, H2C(3), 3J = 7.2); 3.73 (s, 3 H, OMe); 4.04 (d, 1 H, HC(5), 3J = 8.8); 4.25 (dd, 1 H,
HC(6), 3J = 6.3, 3J = 8.8); 4.47 (t, 2 H, H2C(2), 3J = 7.2); 6.15 (dd, 1 H, HC(7), 3J = 6.3,
3J = 16.0); 6.72 (d, 1 H, HC(8), 3J = 16.0); 7.27–7.35 (m, 5 H, Ar)
1.00 (d, 3 H, Me, 3J = 6.8); 2.66 (ddq, 1 H, HC(6), 3J = 5.0, 3J = 7.0, 3J = 6.8); 3.08 (t, 2 H, H2C(3),
3J = 7.1); 3.67 (s, 3 H, OMe); 3.71 (d, 1 H, HC(5), 3J = 7.0); 4.16 (t, 2 H, H2C(2),
3J = 7.1); 5.52 (dd, 1 H, HC(7), 3J = 5.0, 3J = 6.2); 5.87 (d, 1 H, HC(8), 3J = 6.2)
R = Me)
Vb (X = O,
R = Ph)
VIa (X = S,
R = Me)
VIb (X = S,
10
40
50
2.72 (t, 2 H, H2C(3), 3J = 7.1); 3.71 (s, 3 H, OMe); 3.96 (dd, 1 H, HC(6), 3J = 5.0, 3J = 7.8);
4.28 (t, 2 H, H2C(2), 3J = 7.1); 4.42 (d, 1 H, HC(5), 3J = 7.8); 5.48 (dd, 1 H, HC(7), 3J = 7.7,
3J = 5.0); 6.04 (d, 1 H, HC(8), 3J = 7.7); 7.27–7.35 (m, 5 H, Ar)
R = Ph)
VIII
X
0.89 (m, 2 H, CH2 in cyclopropane ring); 0.96 and 1.26 (both m, 1 H each, 2 CH in cyclopropane ring);
1.27 (s, 3 H, Me); 1.33 and 1.74 (both m, 1 H each, CH2CH); 1.47 (m, 2 H, CH2C); 3.63 (s, 3 H, OMe);
3.71–3.91 (m, 4 H, H2C(4) and H2C(5))
1.48 (s, 3 H, Me); 1.87 (t, 4 H, H2C(1'), 3J = 6.7); 2.08 (m, 2 H, H2C(2r')); 2.88 (q, 2 H, H2C(5),
3J = 6.3); 3.69 (m, 1 H, HC(3)); 3.71 (s, 3 H, OMe); 3.78 (dt, 2 H, H2C (6), 3J = 6.3, 3J = 7.8); 5.00
(br d, 2 H, H2C=, 3J = 17.2); 5.82 (ddt, 1 H, =CH, 3J = 6.5, 3J = 10.2, 3J = 17.2)
DOKLADY CHEMISTRY Vol. 414 Part 1 2007