V. A. Soloshonok et al. / Tetrahedron 62 (2006) 6412–6419
6417
2H) ppm; 13C NMR (75 MHz, CDCl3): d 180.5, 177.0,
171.3, 142.2, 133.7, 133.5, 133.2, 132.2, 131.4, 131.2,
130.1, 129.9, 128.9, 128.6, 128.1, 126.4, 126.1, 123.5,
120.7, 70.0, 66.1, 63.2, 57.4, 42.7, 30.7, 25.0 ppm; HRMS
(TOF) [M+Na]+, calcd for [C55H50N6Ni2O6+Na]+:
1029.2397, found: 1029.2396.
3.2.6. 16a and 17a. Yield 72%; 16a/17a¼35:65. Compound
17a: mp 301.3 ꢀC (decomp.); 1H NMR (300 MHz, CDCl3):
d 8.63 (d, J¼8.6 Hz, 2H), 7.47–7.22 (m, 10H), 7.17 (d,
J¼7.4 Hz, 2H), 6.73 (m, 2H), 6.64 (dd, J¼8.0, 1.3 Hz,
2H), 4.08–3.91 (m, 2H), 4.02 (d, J¼16.2 Hz, 2H), 3.28
(quint, J¼7.0 Hz, 1H), 3.02 (d, J¼16.2 Hz, 2H), 2.96–2.83
(m, 3H), 2.60–2.32 (m, 10H), 2.22 (m, 2H), 1.98–1.82 (m,
2H), 1.54–1.30 (m, 8H), 1.00 (t, J¼7.7 Hz, 6H), 0.98 (t,
J¼7.7 Hz, 6H) ppm; 13C NMR (75 MHz, CDCl3): d 176.9,
170.8, 142.7, 133.9, 133.2, 132.7, 130.0, 129.1, 129.0,
127.5, 127.2, 126.4, 123.3, 120.8, 66.6, 62.5, 60.0, 56.7,
53.7, 43.3, 29.0, 26.8, 20.7, 20.6, 13.8 ppm. Compound
16a: mp 275.6 ꢀC (decomp.); 1H NMR (300 MHz,
CDCl3): d 8.56 (dd, J¼8.7, 1.2 Hz, 2H), 7.52–7.18 (m,
10H), 7.02 (d, J¼7.2 Hz, 2H), 6.76 (m, 2H), 6.69 (dd,
J¼8.0, 1.7 Hz, 2H), 4.07 (dd, J¼8.3, 6.1 Hz, 2H), 3.96 (d,
J¼16.3 Hz, 2H), 3.14 (d, J¼16.3 Hz, 2H), 3.03 (m, 2H),
2.72 (m, 2H), 2.68–2.20 (m, 10H), 2.02–1.90 (m, 2H),
1.74–1.60 (m, 2H), 1.58–1.36 (m, 8H), 1.03 (t, J¼7.3 Hz,
6H), 0.99 (t, J¼7.5 Hz, 6H) ppm; 13C NMR (75 MHz,
CDCl3): d 176.8, 176.7, 171.4, 142.5, 133.9, 133.2, 132.8,
130.1, 129.7, 128.7, 127.5, 126.6, 126.3, 123.4, 121.0,
66.4, 63.8, 58.5, 56.9, 53.7, 43.2, 29.4, 24.7, 20.9,
20.8, 13.9 ppm. HRMS (TOF) [M+Na]+, calcd for
[C51H62N6Ni2O6+Na]+: 993.3335, found: 993.3293.
3.2.2. (S,S,S0,R0)-4. Mp 132.9–134.1 ꢀC; Rf 0.17 (CHCl3/
acetone¼4:1); [a]2D3 +4.9 (c 3.3, CHCl3); 1H NMR
(300 MHz, CDCl3): d 8.61–8.57 (m, 1H), 8.32–8.29 (m,
1H), 8.03 (d, J¼7.2 Hz, 2H), 7.82 (d, J¼7.5 Hz, 2H),
7.57–7.02 (m, 18H), 6.72–6.56 (m, 3H), 6.47 (dd, J¼8.1,
1.2 Hz, 1H), 4.37 (d, J¼12.6 Hz, 1H), 4.35 (d, J¼12.9 Hz,
1H), 4.22–4.11 (m, 1H), 3.92 (br s, 1H), 3.83–3.76 (m,
1H), 3.75–3.59 (m, 1H), 3.53–3.33 (m, 5H), 3.22 (m, 1H),
2.84–1.98 (m, 10H) ppm; 13C NMR (75 MHz, CDCl3):
d 181.8, 180.3, 177.6, 177.3, 171.4, 170.8, 143.2, 142.6,
134.1, 133.6, 133.5, 133.4, 133.2, 132.7, 132.4, 132.0,
131.4, 130.9, 129.8, 129.4, 129.2, 128.9, 128.8, 128.8,
127.6, 127.3, 127.1, 126.0, 125.6, 123.3, 123.2, 120.5,
70.3, 68.9, 66.6, 66.5, 62.9, 60.9, 58.9, 57.3, 44.5, 31.0,
30.4, 24.3, 23.0 ppm; HRMS (TOF) [M+Na]+, calcd for
[C55H50N6Ni2O6+Na]+: 1029.2397, found: 1029.2396.
3.2.3. Synthesis of key intermediate 7.17 To a solution of
Ni-complex (S)-2 (500 mg, 1.0 mmol) in benzene (50 mL),
KOH (489 mg, 8.7 mmol), nBu4N+Brꢁ (81 mg, 0.25 mmol),
and CH2Br2 (70 mg, 0.4 mmol) were added in N2 atmo-
sphere. The reaction mixture was stirred at room temperature
for 2 h, quenched with H2O, and then extracted with CH2Cl2.
The combined organic layers were washed with brine, dried
with MgSO4, and concentrated to get a red solid. Silica gel
chromatography (CHCl3/acetone¼10:1 then 5:1) of the
3.2.7. 16b and 17b. Yield 72%; 16b/17b¼44:56. Compound
17b: mp 313.5 ꢀC (decomp.); 1H NMR (300 MHz, CDCl3):
d 8.63 (d, J¼8.6 Hz, 2H), 8.13 (d, J¼7.7 Hz, 4H), 7.66
(d, J¼7.7 Hz, 2H), 7.52–7.02 (m, 26H), 6.60 (m, 2H), 6.43
(d, J¼8.2 Hz, 2H), 4.56 (d, J¼12.3 Hz, 2H), 4.30 (d,
J¼12.7 Hz, 2H), 4.14 (d, J¼16.4 Hz, 2H), 3.81 (s, 2H),
3.61 (d, J¼12.3 Hz, 2H), 3.40 (m, 1H), 3.26 (d, J¼16.3 Hz,
2H), 3.08 (d, J¼16.6 Hz, 2H), 2.98 (m, 1H) ppm; 13C
NMR (75 MHz, CDCl3): d 177.0, 170.9, 142.4, 133.6,
133.1, 132.8, 132.6, 132.3, 132.0, 131.9, 129.8, 129.5,
129.2, 129.0, 128.9, 128.9, 128.8, 128.3, 128.1, 127.4,
127.1, 126.9, 125.5, 123.2, 120.4, 66.5, 64.6, 61.6, 59.6,
53.0, 44.0, 29.6 ppm. Compound 16b: mp 342.2 ꢀC (de-
comp.); 1H NMR (300 MHz, CDCl3): d 8.88–8.22 (m, 4H),
7.94 (d, J¼8.31 Hz, 2H), 7.89–7.82 (m, 4H), 7.58–7.21 (m,
16H), 7.13–6.98 (m, 6H), 6.84 (br d, J¼7.6 Hz, 2H), 6.56
(m, 2H), 6.44 (dd, J¼8.2, 1.5 Hz, 2H), 4.58 (d, J¼13.9 Hz,
2H), 4.35 (dd, J¼8.7, 6.2 Hz, 2H), 4.19 (d, J¼12.2 Hz,
2H), 4.07 (d, J¼16.9 Hz, 2H), 3.90 (d, J¼13.7 Hz, 2H),
3.20 (d, J¼12.0 Hz, 2H), 2.97 (d, J¼16.9 Hz, 2H), 2.87
(dd, J¼8.7, 6.2 Hz, 2H) ppm; 13C NMR (75 MHz, CDCl3):
d 176.6, 176.4, 170.9, 141.7, 133.7, 133.0, 132.7, 131.8,
131.2, 131.0, 130.7, 129.6, 129.4, 129.1, 128.8, 128.6,
128.2, 127.6, 126.3, 126.0, 123.2, 120.3, 65.9, 64.3, 63.6,
61.7, 41.5 ppm. HRMS (TOF) [M+H]+, calcd for
[C63H55N6Ni2O6+H]+: 1107.2890, found: 1107.2972.
1
crude product gave pure product 7 (71 mg, 13% yield). H
NMR (300 MHz, CDCl3): d 8.11 (m, 3H), 7.52–7.13 (m,
9H), 6.86–6.83 (m, 1H), 6.72–6.67 (m, 1H), 5.63 (s, 1H),
4.36 (d, J¼12.3 Hz, 1H), 4.15 (s, 1H), 3.70–3.45 (m, 3H),
3.45 (d, J¼12.6 Hz, 1H), 2.77–2.62 (m, 1H), 2.61–2.41 (m,
1H), 2.26–1.90 (m, 1H) ppm.
3.2.4. (S,S,S0,S0)-12. Yield 37%; mp 342.7 ꢀC (decomp.);
[a]2D3 +1872 (c 0.29, CHCl3); 1H NMR (300 MHz,
CDCl3): d 8.09 (m, 4H), 7.91 (dd, J¼8.6, 1.2 Hz, 2H),
7.56 (dd, J¼8.3, 1.6 Hz, 2H), 7.30–7.35 (m, 4H), 7.14–
7.21 (m, 4H), 6.93 (ddd, J¼8.3, 7.0, 1.2 Hz, 2H), 4.75 (dd,
J¼8.7, 5.8 Hz, 2H), 4.28 (d, J¼12.5 Hz, 2H), 3.58–3.30
(m, 6H), 3.48 (d, J¼12.6 Hz, 2H), 2.96 (dd, J¼8.7, 5.8 Hz,
2H), 2.69 (m, 2H), 2.59–2.40 (m, 2H), 2.46 (s, 6H), 2.00–
2.09 (m, 2H), 2.08–1.97 (m, 2H) ppm; 13C NMR (75 MHz,
CDCl3): d 179.8, 178.7, 168.7, 141.1, 133.4, 131.7, 131.3,
129.0, 128.9, 126.5, 124.3, 121.3, 70.5, 65.9, 63.5, 57.3,
42.6, 30.5, 24.2, 17.9 ppm; HRMS (TOF) [M+Na]+, calcd
for [C45H46N6Ni2O6+Na]+: 905.2083, found: 905.2145.
3.3. Synthesis of 4-aminoglutamic acid (S,S)-1a17
3.2.5. (R*,R0*)-14. Yield 82%; mp 301.5 ꢀC (decomp.); 1H
NMR (300 MHz, CDCl3): d 8.89 (d, J¼8.6 Hz, 2H), 8.20
(d, J¼5.2 Hz, 2H), 7.80 (m, 4H), 7.47–7.22 (m, 14H), 7.05
(d, J¼8.1 Hz, 2H), 6.86 (m, 2H), 4.15 (m, 2H), 2.02 (m,
2H) ppm; 13C NMR (75 MHz, CDCl3): d 179.6, 177.4,
170.0, 152.4, 147.4, 142.6, 139.9, 135.4, 134.4, 133.7,
130.1, 129.6, 128.8, 128.3, 126.9, 126.8, 125.9, 123.7,
123.2, 122.0, 68.2, 35.1 ppm; HRMS (TOF) [M+H]+, calcd
for [C43H30N6Ni2O6+H]+: 843.1, found: 843.2.
Compound (S,S,S0,S0)-3 was decomposed following the pro-
cedure by Belokon and his co-workers, see Ref. 17. Yield
61%; [a]2D5 +20.1 (c 1.35, as HCl salt in D2O).
Acknowledgements
This work was supported by the Department of Chemistry
and Biochemistry, University of Oklahoma. The authors