154
C. S. Jungong, A. V. Novikov / Tetrahedron: Asymmetry 24 (2013) 151–155
4.4.3. tert-Butyl 2-(pentylsulfonyl) diazoacetate 5c
1H NMR (CDCl3, 500 MHz): d 3.34–3.39 (m, 2H), 1.80–1.87 (m,
2H), 1.54 (s, 9H), 1.33–1.47 (m, 4H), 0.93 (t, J = 7 Hz, 3H). 13C
NMR (CDCl3, 125 MHz): d 159.4(C), 85.1(C), 56.6(CH2), 30.3(CH2),
28.5(CH3), 22.6(CH2), 22.3(CH2), 13.9(CH3). IR (CH2Cl2, cmꢀ1):
2128, 1708, 1338, 1146.
21.8(CH3), 19.8(CH3). HRMS (ESI) calcd for C10H22O4NS [M+NH4]+
252.1269, found 252.1390.
4.5.4. trans-tert-Butyl tetrahydro-3-methyl-2H-thiopyran-1,1-
dioxide-2-carboxylate 6c
1H NMR (CDCl3, 500 MHz): d 3.44 (d, J = 11 Hz, 1H), 3.14 (dt,
J = 14, 4 Hz, 1H), 2.84–2.92 (m, 1H), 2.46–2.56 (m, 1H), 2.06–2.21
(m, 2H), 1.90–1.97 (m, 1H), 1.53 (s, 9H), 1.20–1.30 (m, 1H), 1.08
(d, J = 6 Hz, 3H). 13C NMR (CDCl3, 125 MHz): d 163.0(C), 83.9(C),
73.4(CH), 52.0(CH2), 34.5(CH), 32.0(CH2), 28.1(CH3), 22.9(CH2),
19.8(CH3). HRMS (ESI) calcd for C11H24O4NS [M+NH4]+ 266.1426,
found 266.1383.
4.4.4. 2,4-Dimethylpentan-3-yl 2-(pentylsulfonyl)diazoacetate
5d
1H NMR (CDCl3, 500 MHz): d 4.75 (t, J = 6 Hz, 1H), 3.35–3.40 (m,
2H), 1.93–2.01 (m, 2H), 1.79–1.87 (m, 2H), 1.32–1.46 (m, 4H),
0.89–0.94 (m, 15H). 13C NMR (CDCl3, 125 MHz): d 160.6(C),
86.2(CH), 56.7(CH2), 30.3(CH2), 29.7 (CH), 22.8(CH2), 22.3(CH2),
19.7(CH3), 17.4(CH3), 13.9(CH3). IR (CH2Cl2, cmꢀ1): 2130, 1709,
1338, 1147.
4.5.5. trans-2,4-Dimethylpentan-3-yl tetrahydro-3-methyl-2H-
thiopyran-1,1-dioxide-2-carboxylate 6d
1H NMR (CDCl3, 500 MHz): d 4.75 (t, J = 6 Hz, 1H), 3.60 (d,
J = 11 Hz, 1H), 3.16 (dt, J = 14, 4 Hz, 1H), 2.92 (td, J = 13, 4 Hz,
1H), 2.51–2.61 (m, 1H), 2.07–2.23 (m, 2H), 1.91–2.01 (m, 3H),
1.23–1.33 (m, 1H), 1.10 (d, J = 6 Hz, 3H), 0.96 (d, J = 7 Hz, 3H),
0.96 (d, J = 7 Hz, 3H), 0.91 (t, J = 7 Hz, 6H). 13C NMR (CDCl3,
125 MHz): d 164.1(C), 86.1(CH), 72.9(CH), 52.1(CH2), 34.3(CH),
32.1(CH2), 29.7(CH), 29.5(CH), 22.8(CH2), 20.3(CH3), 19.8(CH3),
17.7(CH3), 17.2(CH3). HRMS (ESI) calcd for C14H30NO4S [M+NH4]+
308.1895, found 308.1877. Note: accidental equivalence of two
methyls at 19.8.
4.4.5. (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl 2-(pentylsulfo-
nyl)diazoacetate 5e
½
a 2D0
ꢂ
¼ ꢀ56:5 (c 0.021, CHCl3). 1H NMR (CDCl3, 500 MHz): d 4.86
(td, J = 11, 4.5 Hz, 1H), 3.31–3.42 (m, 2H), 2.02–2.08 (m, 1H), 1.78–
1.89 (m, 3H), 1.66–1.74 (m, 2H), 1.31–1.56 (m, 6H), 1.02–1.12 (m,
2H), 0.83–0.94 (m, 10H), 0.78 (d, J = 7 Hz, 3H). 13C NMR (CDCl3,
125 MHz): d 160.0(C), 77.3(CH), 56.7(CH2), 47.2(CH), 41.1(CH2),
34.2(CH2), 31.6(CH), 30.3(CH2), 26.6(CH), 23.6(CH2), 22.6(CH2),
22.3(CH2), 22.1(CH3), 20.9(CH3), 16.5(CH3), 13.9(CH3). IR (CH2Cl2,
cmꢀ1): 2131, 1705, 1336, 1146.
4.5.6. (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl (2R,3R)-tet-
rahydro-3-methyl-2H-thiopyran-1,1-dioxide-2-carboxylate 6e
4.4.6. (1S,2R,5S)-2-Isopropyl-5-methylcyclohexyl 2-(pentylsulfo-
nyl)diazoacetate [enantiomer of 5e, from (+)-menthol]
½
a 2D0
ꢂ
¼ ꢀ28:7 (c 0.013, CHCl3). 1H NMR (CDCl3, 500 MHz): d 4.84
Spectroscopic data identical to 5e. ½a D20
¼ þ54:7 (c 0.035,
ꢂ
(td, J = 11, 4.5 Hz, 1H), 3.54 (d, J = 11 Hz, 1H), 3.15 (dt, J = 14, 4 Hz,
1H), 2.90 (td, J = 14, 4 Hz, 1H), 2.50–2.60 (m, 1H), 2.08–2.23 (m,
3H), 1.92–2.01 (m, 2H), 1.66–1.74 (m, 2H), 1.44–1.54 (m, 2H),
1.21–1.31 (m, 1H), 1.02–1.14 (m, 5H), 1.07 (d, J = 6.5 Hz), 0.84–
0.95 (m, 7H), 0.92 (d, J = 6.5 Hz), 0.91 (d, J = 6.5 Hz), 0.77 (d,
J = 7 Hz, 3H). 13C NMR (CDCl3, 125 MHz): d 163.5(C), 77.4(CH),
73.1(CH), 52.1(CH2), 46.9(CH), 40.6(CH2), 34.4(CH), 34.4(CH2),
32.1(CH2), 31.7(CH), 26.2(CH), 23.3(CH2), 22.9(CH2), 22.1(CH3),
21.0(CH3), 19.8(CH3), 16.1(CH3). HRMS (ESI) calcd for C17H34NO4S
[M+NH4]+ 348.2208, found 348.2206.
CHCl3).
4.5. General procedure for C–H insertion
To a solution of Rh(II) catalyst (1 mol %) in CH2Cl2 (2.5 mL/
mmol) was added the corresponding diazo alkyl 2-(pentylsulfo-
nyl)acetate (1 equiv) dissolved in CH2Cl2 (2.5 mL/mmol) over
2 h via syringe pump. The resulting mixture was stirred at room
temperature for 12 h after which time the reaction was complete
as indicated by TLC analysis. The reaction mixture was then
evaporated under reduced pressure to afford the crude product
which was purified by flash chromatography using EtOAC–
Hexanes.
For entries 6 and 7 in Table 2, inseparable mixtures of 6e and its
diastereomer were obtained. They were directly reduced to alcohol
10 for determination of the ratio.
4.6. Reduction of esters 6a–6e, and 2
4.5.1. trans-Ethyl tetrahydro-3-methyl-2H-thiopyran-1,1-diox-
ide-2-carboxylate 2
The data matched that previously reported.3
To the corresponding thiopyran-1,1-dioxide carboxylate
(1 equiv) in CH2Cl2 (2.5 mL/mmol) was added DIBALH (2.2 equiv)
and the resulting mixture stirred at room temperature for 12 h.
The reaction was then quenched with MeOH (0.7 mL). Next, a
10% solution of Rochelle salt (5 mL) was added and stirred vigor-
ously for several hours, until the solids disappeared. The water
layer was extracted with CH2Cl2 (3 ꢁ 5 mL) and then EtOAc
(5 mL). The combined organic extracts were washed with brine,
dried over anhydrous Na2SO4 and concentrated to afford a crude
product, which was purified by flash chromatography using
EtOAC–Hexanes (1:4–1:1).
4.5.2. trans-Methyl tetrahydro-3-methyl-2H-thiopyran-1,1-diox-
ide-2-carboxylate 6a
1H NMR (CDCl3, 500 MHz): d 3.86 (s, 3H), 3.58 (d, J = 11 Hz,
1H), 3.18 (dt, J = 14, 4 Hz, 1H), 2.88–2.96 (m, 1H), 2.52–2.62
(m, 1H), 2.09–2.23 (m, 2H), 1.94–2.01 (m, 1H), 1.23–1.33 (m,
1H), 1.07 (d, J = 7 Hz, 3H). 13C NMR (CDCl3, 125 MHz):
d
164.5(C), 72.7(CH), 53.4(CH3), 52.0(CH2), 34.5(CH), 32.0(CH2),
22.9(CH2), 20.0(CH3). HRMS (ESI) calcd for C8H15O4S [M+H]+
207.0691, found 207.0668.
4.6.1. trans-(Tetrahydro-3-methyl-2H-thiopyran-1,1-dioxide-2-
yl)methanol 10
4.5.3. trans-Isopropyl tetrahydro-3-methyl-2H-thiopyran-1,1-
dioxide-2-carboxylate 6b
Mp 94–95 °C. 1H NMR (CDCl3, 500 MHz): d 4.45 (dd, J = 13,
3.5 Hz, 1H), 4.00 (ddd, J = 5.5, 9, 14 Hz, 1H), 3.11 (dt, J = 14,
3.5 Hz, 1H), 2.90–2.98 (m, 1H), 2.60 (dd, J = 11.5, 5.5 Hz, 1H), 2.50
(dd, J = 9, 4.5, 1H), 2.34–2.44 (m, 1H), 2.06–2.19 (m, 2H), 1.92
(dd, J = 14.5, 3 Hz, 1H), 1.28–1.37 (m, 1H), 1.14 (d, J = 6.5 Hz, 3H).
13C NMR (CDCl3, 125 MHz): d 68.4(CH), 56.2(CH2), 52.2(CH2),
1H NMR (CDCl3, 500 MHz): d 5.18 (septet, J = 6.5 Hz, 1H), 3.52
(d, J = 11 Hz, 1H), 3.16 (dt, J = 14, 4 Hz, 1H), 2.86–2.94 (m, 1H),
2.51–2.61 (m, 1H), 2.08–2.23 (m, 2H), 1.93–1.99 (m, 1H), 1.33 (d,
J = 6.5 Hz, 3H), 1.32 (d, J = 6.5 Hz, 3H), 1.23–1.30 (m, 1H), 1.08 (d,
J = 6.5 Hz, 3H). 13C NMR (CDCl3, 125 MHz): d 163.5(C), 72.9(CH),
70.6(CH), 52.0(CH2), 34.5(CH), 32.0(CH2), 22.8(CH2), 21.9(CH3),