82.7, 73.7, 56.0, 53.5, 43.1, 37.2, 36.8, 27.9, 16.8; IR (neat) 3405,
1729, 1670, 1634, 1503, 1368, 1258 cm-1; MS (ESI, m/z) 536.1
(M + Na)+; HRMS (ESI, m/z) calcd for C29H36NO5NaCl (M +
Na)+ 536.2180, found 536.2200.
ing to room temperature. After 2 h, the solution was concen-
trated and then reconcentrated with dry toluene to give a white
solid. The crude solid was dissolved in 15 mL of DMF, and to
this solution was added 68 mg (0.2 mmol) of FDPP in 10 mL of
DMF followed by 74 µL (0.43 mmol) of diisopropylethylamine.
The yellow solution was stirred at 23 °C under argon. After 12
h, 40 mL of ethyl acetate was added. The organic layer was
washed with 40 mL of 1 N HCl, 40 mL of H2O, and 40 mL of
brine and finally dried over Na2SO4. After filtration and
concentration the crude product was purified by flash silica gel
chromatography (45% to 60% ethyl acetate/hexanes) to give 57
(2S)-2-[3′(ter t-Bu t yloxyca r b on yl)a m in o-2′,2′-d im et h yl-
p r op a n oyloxy]-4-m eth ylp en ta n oic Acid (5). To a stirring
solution of 143 mg (0.76 mmol) of BOC-protected amino acid 16
and 116 mg (0.52 mmol) of benzyl ester 17 in 12 mL of CH2Cl2
at 0 °C were added 148 mg (0.77 mmol) of EDCI and 95 mg (0.77
mmol) of DMAP. Stirring was continued at 23 °C for 17 h. After
this period, 10 mL of water and 10 mL of CH2Cl2 were added.
The layers were separated, and the organic layer was washed
with 10% aqueous HCl, saturated NaHCO3 solution, and brine.
The solution was dried over Na2SO4, filtered, and concentrated.
The residue was purified by flash silica gel chromatography (8%
mg (61% yield) of macrolactam as a white amorphous solid. [R]23
D
+26.2 (c 0.5); [lit.16 [R]23 +26.4 (c 0.25, CHCl3)]; H NMR (400
1
D
MHz, CDCl3) δ 7.21-7.33 (m, 6H), 7.2 (d, 1H, J ) 1.9), 7.05 (dd,
1H, J ) 2.0, 8.4), 6.84 (d, 1H, J ) 8.4), 6.77 (ddd, 1H, J ) 4.4,
10.8, 15.1), 6.4 (d, 1H, J ) 15.8), 6.01 (dd, 1H, J ) 8.8, 15.8),
5.75 (d, 1H, J ) 15.2), 5.56 (d, 1H, J ) 7.8), 5.05 (m, 1H), 4.84
(dd, 1H, J ) 3.4, 10.1), 4.74 (dd, 1H, J ) 6.6, 13.3 Hz), 3.87 (s,
3H), 3.41 (dd, 1H, J ) 8.6, 13.5), 3.12 (d, 1H, J ) 3.3 Hz), 3.07-
3.09 (m, 2H), 2.55 (m, 2H), 2.38 (ddd, 1H, J ) 11, 11.3, 14.3),
1.66 (m, 1H), 1.61 (m, 1H), 1.32 (ddd, 1H, J ) 3.5, 8.4, 13.2),
1.22 (s, 3H), 1.15 (s, 3H), 1.13 (d, 3H, J ) 6.9), 0.73 (d, 3H, J )
6.9), 0.72 (d, 3H, J ) 6.9); 13C NMR (100 MHz, CDCl3) δ 178,
170.5, 170.2, 165, 154, 142.2, 136.5, 131.7, 130.8, 130.1, 129.5,
128.5, 128.2, 127.5, 126.1, 124.4, 122.5, 112.2, 77, 71.4, 56.1, 54.2,
46.4, 42.6, 42.2, 39.4, 36.5, 35.2, 24.5, 22.8, 22.7, 22.6, 21.1, 17.3;
EtOAc/hexanes) to give 172 mg (78%) of ester product as a yellow
1
oil. [R]23 -40.5 (c 0.64, CHCl3); H NMR (400 MHz, CDCl3) δ
D
7.36 (m, 5H), 5.41 (t, 1H, J ) 6.3), 5.18 (dd, 2H, J ) 12.2, 24),
5.09 (dd, 1H, J ) 3.6, 9.8), 3.28 (m, 2H), 1.81 (m, 1H), 1.76-
1.62 (m, 2H), 1.43 (s, 9H), 1.20 (s, 6H), 0.92 (dd, 6H, J ) 6.3,
10.0); 13C NMR (100 MHz, CDCl3) δ 176.4, 170.8, 156.3, 135.0,
128.5, 128.4, 128.3, 78.9, 70.8, 67.1, 48.5, 43.9, 39.3, 28.3, 24.7,
23.0, 22.9, 22.2, 21.4; IR (neat) 3392, 1737, 1721, 1510 cm-1
.
A mixture of 778 mg (1.85 mmol) of the above ester and 81
mg of 10% Pd-C in 25 mL of ethyl acetate was stirred at 23 °C
under a H2 balloon for 1.5 h. The mixture was then filtered
through Celite and concentrated. The crude product was sub-
jected to flash silica gel chromatography (10% MeOH/CH2Cl2)
IR (neat) 3413, 3276, 1747, 1721, 1658, 1536, 1504, 1259 cm-1
;
MS (ESI, m/z) 675.3 (M + Na)+; HRMS (ESI, m/z) calcd for
C36H45N2O7NaCl (M + Na)+ 675.2813, found 675.2822.
to give the acid 5 in quantitative yield as a colorless oil. [R]23
D
-32.5 (c 0.55, MeOH); lit.5 [R]23 -29.9 (c 1.1, MeOH); 1H NMR
Cr yp top h ycin 52 (2). To a stirring solution of 53 mg (0.08
mmol) of macrolactam 17 in 5 mL of CH2Cl2 at 0 °C was added
29 mg (0.17 mmol) of m-CPBA. After dissolution, the ice bath
was removed, and stirring was continued with warming to 23
°C for 12 h. The solution was diluted with 25 mL of ethyl acetate,
and the organic layer was washed successively with 10 mL of
5% NaHCO3 solution, 10 mL of water, and 10 mL of brine. After
drying over Na2SO4, filtration, and concentration, the crude
D
(400 MHz, CDCl3) δ 5.4 (m, 1H), 5.08 (dd, 1H, J ) 3.4, 9.7), 3.28
(m, 2H), 1.7-1.9 (m, 3H), 1.42 (s, 9H), 1.22 (s, 3H), 1.20 (s, 3H),
0.97 (d, 3H, J ) 6.3 Hz), 0.93 (d, 3H, J ) 6.1); 13C NMR (100
MHz, CDCl3) δ 176.5, 175.5, 156.5, 79.1, 70.5, 48.5, 43.9, 39.4,
28.3, 24.7, 23.1, 22.1, 21.3; IR (neat) 3349, 1725, 1672, 1524,
1368 cm-1; MS (ESI m/z) 354.2 (M + Na)+.
(2S)-2-(3-ter t-Bu t oxyca r b on yla m in o-2,2-d im et h yl-p r o-
p ion yloxy)-4-m et h yl-p en t a n oic Acid (1S,2R,2E)-1-{3-[1-
ter t-Bu toxyca r bon yl-(2R)-2-(3-ch lor o-4-m eth oxy-p h en yl)-
et h ylca r b a m oyl]-a llyl}-2-m et h yl-4-p h en yl-b u t -(3E)-en yl
Ester (18). To a stirring solution of 117 mg (0.48 mmol) of 2,4,6-
trichlorobenzoyl chloride in 5 mL of THF was added 139 mg (0.42
mmol) of acid 5 in 15 mL of THF followed by 78 µL (0.56 mmol)
of Et3N. The resulting mixture was continued to stir at 23 °C
for 3.5 h and then concentrated.
1
product (a 2:1 mixture of epoxides by H NMR) was purified by
reverse-phase HPLC (YMC ODS-AQ S5 120 Å, 4.6 mm × 250
mm, 45% H2O/CH3CN, λ ) 254 nm, 0.9 mL/min; Cryptophycin
52 (2) retention time ) 53.35 min; Cryptophycin epoxide
diastereomer, retention time ) 58.25 min, in (38 mg) 70% yield.
Cryptophycin 52 (white amorphous solid). [R]23 +20 (c 0.08);
D
[lit.16 [R]23 +19.9 (c 0.5, CHCl3)]; 1H NMR (400 MHz, CDCl3) δ
D
7.33-7.39 (m, 3H), 7.20-7.26 (m, 3H), 7.19 (d, 1H, J ) 2.0),
7.05 (dd, 1H, J ) 1.9, 8.4), 6.84 (d, 1H, J ) 8.4), 6.76 (ddd, 1H,
J ) 4.3, 10.7, 15), 5.71 (d, 1H, J ) 15.2), 5.44 (d, 1H, J ) 7.8
Hz), 5.21 (dd, 1H, J ) 4.7, 9.6 Hz), 4.82 (dd, 1H, J ) 3.4, 10.1),
4.74 (dd, 1H, J ) 6.4, 14 Hz), 3.88 (s, 3H), 3.68 (d, 1H, J ) 1.6),
3.42 (dd, 1H, J ) 8.7, 13.5), 3.11 (d, 1H, J ) 3.3), 3.08 (d, 2H, J
) 5.7), 2.92 (dd, 1H, J ) 1.7, 7.6), 2.58 (m, 1H), 2.45 (ddd, 1H,
J ) 10.9, 11, 14.4), 1.78 (m, 1H), 1.72 (m, 1H), 1.67 (m, 1H),
1.32 (m, 1H), 1.22 (s, 3H), 1.16 (s, 3H), 1.14 (d, 3H, J ) 7.5),
0.85 (d, 3H, J ) 6.6), 0.83 (d, 3H, J ) 6.6); 13C NMR (100 MHz,
CDCl3) δ 178.1, 170.5, 170.2, 164.9, 154.1, 141.9, 136.7, 130.9,
129.3, 128.7, 128.6, 128.3, 125.6, 124.6, 122.6, 112.3, 75.9, 71.2,
63.1, 59.1, 56.1, 54.2, 46.4, 42.7, 40.7, 39.3, 36.9, 35.3, 24.6, 22.9,
22.8, 22.7, 21.2, 13.7; IR (neat) 3409, 3263, 1747, 1719, 1653,
1539, 1505, 1259 cm-1; MS (ESI, m/z) 691.3 (M + Na)+; HRMS
(ESI, m/z) calcd for C36H45N2O8NaCl (M + Na)+ 691.2762, found
691.2767.
To a stirring mixture of crude mixed anhydride in 5 mL of
toluene was added 185 mg (0.36 mmol) of 15 in 8.5 mL of toluene,
56 µL (0.4 mmol) of Et3N, and finally 5.5 mg (0.04 mmol) of
DMAP. The mixture was stirred at 23 °C under N2 for 30 min.
After this period, 10 mL of 0.1 N HCl followed by 15 mL of ethyl
acetate were added. The layers were separated, and the organic
layer was washed with 5 mL of brine, dried over Na2SO4, and
concentrated. The crude product was purified by flash silica gel
chromatography (25% and 30% ethyl acetate/hexanes) to give
229 mg of 18 as a white solid in 77% yield. Mp 45-47 °C [R]23
D
1
-23 (c ) 1.0, CHCl3); H NMR (400 MHz, CDCl3) δ 7.28-7.33
(m, 4H), 7.22 (m, 1H), 7.15 (d, 1H, J ) 1.9), 7.02 (dd, 1H, J ) 2,
8.5), 6.84 (d, 1H, J ) 8.5), 6.82 (m, 1H), 6.42 (d, 1H, J ) 15.7),
6.41 (d, 1H, J ) 7.7), 6.02 (dd, 1H, J ) 8.6, 15.7), 5.89 (d, 1H, J
) 15.6), 5.44 (t, 1H, J ) 6.5), 5.05 (td, 1H, J ) 5.9, 6.0), 4.93
(dd, 1H, J ) 3.6, 9.6), 4.78 (dd, 1H, J ) 5.8, 13.3), 3.85 (s, 3H),
3.26 (d, 2H, J ) 6.6), 3.04 (m, 2H), 2.63 (m, 1H), 2.54 (m, 2H),
1.64-1.76 (m, 2H), 1.55 (m, 1H), 1.43 (s, 9H), 1.42 (s, 9H), 1.20
(s, 3H), 1.15 (s, 3H), 1.11 (d, 3H, J ) 6.9), 0.86 (d, 3H, J ) 6.4),
0.82 (d, 3H, J ) 6.4); 13C NMR (100 MHz, CDCl3) δ 176, 170.8,
170.3, 165, 156.5, 153.9, 139, 136.9, 131.7, 131.4, 130.1, 129.5,
128.8, 128.6, 127.5, 126.2, 125.8, 121.9, 111.8, 82.5, 79, 76.5, 71.2,
56.1, 53.7, 48.6, 44, 40.9, 39.5, 36.9, 33.5, 28.4, 28, 24.8, 23.0,
22.8, 22.3, 21.4, 16.7; IR (neat) 3378, 1731, 1677, 1503, 1366,
1257 cm-1; MS (ESI, m/z) 849.3; HRMS (ESI, m/z) calcd for
C45H63N2O10ClNa (M + Na)+ 849.4069, found 849.4095.
Ack n ow led gm en t. This research was supported in
part by the National Institutes of Health.
Su p p or tin g In for m a tion Ava ila ble: Experimental de-
1
tails for compounds 4, 9-11, H NMR and 13C NMR spectra
for compounds 2, 4, 5, 9-11, 13, 15, and 18-19. This material
Cr yp top h ycin 51 (19). To a stirring solution of 117 mg (0.14
mmol) of 18 in 3 mL of CH2Cl2 at 0 °C was added 1.6 mL (20.8
mmol) of CF3COOH slowly. Stirring was continued with warm-
J O035077V
9826 J . Org. Chem., Vol. 68, No. 25, 2003