General and Scalable Amide Bond Formation with Epimerization-Prone Substrates Using T3P and Pyridine

General and Scalable Amide Bond ormation with Epimerization-Prone Substrates Using T3P and Pyridine Joshua R. Dunetz,*,a Yanqiao Xiang, b Aaron Baldwin, b Justin Ringling b a Chemical Research and Development b Analytical Research and Development Pharmaceutical Sciences, Pfizer Worldwide Research and Development Eastern Point Road, Groton, Connecticut 06340 joshua.r.dunetz@pfizer.com Table of Contents Materials, Instrumentation, Chiral Assays S1 S2 Procedures for synthesis of amides 1, 7a g, 8a b, 9a b, 10 S2 S10 Chiral PLC/SC chromatograms of amides 1, 7a g, 8a b, 9a b, 10 S11 S17 1, 13 C MR spectra of amides 1, 7a g, 8a b, 9a b, 10 S18 S43 Materials. Common substrates, reagents, and solvents were obtained from commercial suppliers and used without further purification. Commercial solutions of T3P (50% in EtAc) were purchased from Aldrich or Alfa Aesar. The preparation of acid 2 and amine 3 will be disclosed in a future publication. Instrumentation. 1 and 13 C MR spectra were obtained on a Varian MR 400 Mz spectrometer. 1 MR chemical shifts are expressed in parts per million (δ) downfield from tetramethylsilane (with the central peak of DMS referenced to 2.50 ppm). 13 C MR chemical shifts are expressed in parts per million (δ) downfield from tetramethylsilane (with the central peak of DMS referenced to 39.51 ppm). igh-resolution positive electrospray ionization mass spectrometric data (RMS-ESI) were obtained using a Thermo LTQ-TICR ultra mass S-1

spectrometer. Melting points were acquired using a Thomas oover UniMelt Capillary Melting Point Apparatus. Chiral Assays. Analytical methods to determine the enantiomeric ratio of amide products were developed using racemic samples. Amides 1 and 7a were evaluated by chiral PLC via AD-R column at 40 C using 70% MeC/ 2 (flow rate = 0.8 ml/min). Amides 7b, 7c, and 7e were evaluated by chiral SC via IC column at 40 C using 5 50% gradient of Me/scC 2 at 6.5%/min with hold for 1 min at 50% Me (flow rate = 4 ml/min). 1 Amides 7d and 8b were evaluated by chiral SC via AD column at 40 C using 5 50% gradient of Me/scC 2 at 6.5%/min with hold for 1 min at 50% Me (flow rate = 4 ml/min). Amides 7f, 7g, 8a, and 9b were evaluated by chiral SC via D column at 40 C using 5 50% gradient of Me/scC 2 at 6.5%/min with hold for 1 min at 50% Me (flow rate = 4 ml/min). Amides 9a and 10 were evaluated by chiral SC via J column at 40 C using 5 50% gradient of Me/scC 2 at 6.5%/min with hold for 1 min at 50% Me (flow rate = 4 ml/min). General Procedure for Amide Coupling. Synthesis of (S)-benzyl 6-(3-cyclopentyl-2- (4-(trifluoromethyl)-1-imidazol-1-yl)propanamido)nicotinate (1). Gram scale: A 250-mL, jacketed reaction vessel equipped with overhead stirrer and internal temperature probe was charged with acid 2 (10.10 g, 36.56 mmol; 99.7 : 0.3 er), amine 3 (9.20 g, 40.3 mmol, 1.1 equiv), pyridine (10 ml, 120 mmol, 1 volume), and EtAc (20 ml, 2 volumes). The heterogeneous mixture was cooled between 20 C and 10 C as 44 ml of T3P solution (50 wt% in EtAc, 74 mmol, 2.0 equiv) were added via addition funnel at a rate to maintain an internal temperature below 0 C. The resulting homogeneous, golden-yellow solution was stirred at 0 C for 20 h, at which time the coupling was complete and amide 1 was formed with 99.0 : 1.0 er. Cooled between 20 C and 10 C as 30 ml (3 volumes) of 0.5 M aq Cl solution were added (exothermic) via addition funnel at a rate to maintain an internal temperature below 5 C. The quenched mixture was stirred at 20 C for 2 h, and the thick solids were collected on a Buchner funnel and rinsed with three 100-mL portions of water. The solids were transferred to a clean vessel with 100 ml of water and granulated for 1 h. The slurry was 1 scc 2 = supercritical carbon dioxide S-2

filtered through a Buchner funnel, and the filter cake was rinsed with 50 ml of water and dried (vacuum oven at 50 C) to obtain 14.70 g of amide 1 (83% yield, 99.4 : 0.6 er) as a white solid. Kilogram scale: A 200-L, jacketed reactor was charged with acid 2 (15.00 kg, 54.23 mol; 99.6 : 0.4 er), amine 3 (13.60 kg, 59.56 mol, 1.1 equiv), pyridine (15.1 L, 187 mol, 1 volume), and EtAc (29.7 L, 2 volumes). The heterogeneous mixture was held at 10 C (jacket) as 64.9 L of T3P solution (50 wt% in EtAc, 108 mol, 2.0 equiv) were added (exothermic) over 1.5 h while maintaining an internal temperature below 0 C. The resulting homogeneous, goldenyellow solution was held at 0 C for 20 h, at which time the coupling was complete and amide 1 was formed with 98.5 : 1.5 er. The solution was held at 10 C (jacket) as 46 L (3 volumes) of 0.5 M aq Cl solution were added (exothermic) at a rate to maintain an internal temperature below 5 C. The quenched mixture was mixed at 20 C for 4 h, and the thick solids were collected on a utsche filter and rinsed with 50 L of water. The filter cake was dried under 2 for 1 h, returned to the 200-L reactor, and reslurried in 150 L of water for 2 h. The fine solids were collected on a utsche filter, rinsed with 50 L of water, and dried under 2 for 1 h. The filter cake was dried in a vacuum oven with 2 sweep at 50 C to obtain 22.42 kg of amide 1 (85% yield, 99.1 : 0.9 er) as a white solid: mp 170 171 C; 1 MR (400 Mz, d 6 -DMS) δ 11.56 (s, 1); 8.91 (dd, J = 0.8, 2.4 z, 1), 8.34 (dd, J = 2.4, 8.8 z, 1), 8.17 (d, J = 8.8 z, 1), 7.97 7.99 (m, 2), 7.33 7.50 (m, 5), 5.36 (s, 2), 5.27 (dd, J = 4.8, 10.0 z, 1), 2.20 (m, 1), 2.10 (m, 1), 1.27 1.69 (m, 8), 1.07 (m, 1); 13 C MR (100 Mz, d 6 -DMS): δ 168.9, 164.1, 154.7, 149.6, 139.7, 138.9, 135.9, 130.0 (q, J C = 38 z), 128.5, 128.2, 128.1, 122.1 (q, J C = 265 z), 121.5, 120.1 (q, J C = 4 z), 113.0, 66.3, 60.0, 37.5, 36.2, 32.0, 30.8, 24.6, 24.4; RMS-ESI m/z: [M+] + calcd for C 25 25 3 4 3, 487.1952; found, 487.1955. (S)--phenyl-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)propanamide (7a). A mixture of acid 2 (2.6 g, 9.4 mmol; 98.1 : 1.9 er), aniline (0.94 ml, 0.96 g, 10 mmol), and pyridine (2.6 ml, 32 mmol) in 5.2 ml of EtAc at 10 C was treated with T3P (11 ml, 50 wt% in EtAc, 18 mmol) according to the general procedure. The coupling proceeded to completion within 16 h at 0 C, and amide 7a was formed in 97.7 : 2.3 er. The solution was quenched at 10 C with 7 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 30 ml of EtAc and the phases were separated. The S-3

organic layer was washed with 20 ml of 0.5 M aq Cl, 20 ml of satd acl solution, and concentrated to 3.42 g of an off-white solid. Column chromatography on 130 grams of silica gel (gradient elution with 35 40% EtAc/hexanes) provided 3.15 g of amide 7a (95% yield) as an off-white solid: 1 MR (400 Mz, d 6 -DMS) δ 10.42 (s, 1); 7.98 (s, 1), 7.95 (s, 1), 7.58 (d, J = 7.6 z, 2), 7.33 (dd, J = 7.6 z, 2), 7.09 (t, J = 7.6 z, 1), 5.06 (dd, J = 6.0, 9.6 z, 1), 2.03 2.21 (m, 2), 1.40 1.74 (m, 7), 1.25 (m, 1), 1.09 (m, 1); 13 C MR (100 Mz, d 6 -DMS): δ 167.4, 138.7, 138.3, 129.9 (q, J C = 38 z), 128.9, 124.0, 122.1 (q, J C = 265 z), 120.0 (q, J C = 4 z), 119.6, 60.3, 38.1, 36.3, 32.0, 31.2, 24.7, 24.5; RMS-ESI m/z: [M+] + calcd for C 18 20 3 3, 352.1631; found, 352.1632. (S)--methyl--phenyl-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)- propanamide (7b). A mixture of acid 2 (3.23 g, 11.7 mmol; 98.1 : 1.9 er), -methylaniline (1.4 ml, 1.4 g, 13 mmol), and pyridine (3.3 ml, 41 mmol) in 6.5 ml of EtAc at 20 C was treated with T3P (14 ml, 50 wt% in EtAc, 24 mmol) according to the general procedure. The coupling proceeded to completion within 19 h at 0 C, and amide 7b was formed in 97.0 : 3.0 er. The solution was quenched at 20 C with 10 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 100 ml of EtAc, washed with three 50-mL portions of 1 M aq Cl, and concentrated to 4.57 g of a viscous, golden-yellow oil. Column chromatography on 100 grams of silica gel (gradient elution with 15 20% EtAc/hexanes) provided 3.80 g of amide 7b (89% yield) as a colorless oil: 1 MR (400 Mz, d 6 -DMS) δ 7.88 (s, 1), 7.81 (s, 1), 7.45 7.56 (m, 5), 4.85 (dd, J = 3.6, 10.4 z, 1), 3.18 (s, 3), 2.05 (m, 1), 1.70 (m, 1), 1.15 1.46 (m, 7), 0.88 (m, 1), 0.38 (m, 1); 13 C MR (100 Mz, d 6 -DMS): δ 168.1, 142.3, 138.9, 130.1, 129.6 (q, J C = 38 z), 128.4, 127.7, 122.1 (q, J C = 265 z), 120.3 (q, J C = 4 z), 56.6, 37.8, 37.6, 35.5, 31.9, 30.2, 24.3, 24.1; RMS-ESI m/z: [M+] + calcd for C 19 22 3 3, 366.1788; found, 366.1781. (S)--(4-methoxyphenyl)-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)- propanamide (7c). A mixture of acid 2 (1.78 g, 6.44 mmol; 98.1 : 1.9 er), p-anisidine (0.87 g, 7.1 mmol), and pyridine (1.8 ml, 22 mmol) in 3.6 ml of EtAc at 15 C was treated with T3P (8.0 ml, 50 wt% in EtAc, 13 mmol) according to the general procedure. The coupling proceeded to completion within 22 h at 0 C, and amide 7c was formed in 95.7 : 4.3 er. The S-4

solution was quenched at 15 C with 6 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 20 ml of EtAc, washed with three 20-mL portions of 0.5 M aq Cl, and concentrated to 2.55 g of a purple solid. Column chromatography on 100 grams of silica gel (elution with 40% EtAc/hexanes) provided 2.41 g of amide 7c (98% yield) as a pale green solid: 1 MR (400 Mz, d 6 -DMS) δ 10.29 (s, 1), 7.97 (s, 1), 7.94 (s, 1), 7.49 (d, J = 8.8 z, 2), 6.90 (d, J = 8.8 z, 2), 5.02 (dd, J = 6.0, 9.6 z, 1), 3.72 (s, 3), 2.05 2.18 (m, 2), 1.40 1.75 (m, 7), 1.25 (m, 1), 1.08 (m, 1); 13 C MR (100 Mz, d 6 -DMS): δ 166.8, 155.7, 138.7, 131.3, 129.8 (q, J C = 37 z), 122.1 (q, J C = 265 z), 121.1, 119.9 (q, J C = 4 z), 113.9, 60.2, 55.1, 38.2, 36.3, 32.0, 31.2, 24.6, 24.5; RMS-ESI m/z: [M+] + calcd for C 19 22 3 3 2, 382.1737; found, 382.1738. (S)--(2,6-dimethylphenyl)-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)- propanamide (7d). A mixture of acid 2 (2.91 g, 10.5 mmol; 98.1 : 1.9 er), 2,6-dimethylaniline (1.4 ml, 1.4 g, 11 mmol), and pyridine (2.9 ml, 36 mmol) in 5.8 ml of EtAc at 20 C was treated with T3P (13 ml, 50 wt% in EtAc, 21 mmol) according to the general procedure. The coupling proceeded to completion within 18 h at 0 C, and amide 7d was formed in 97.3 : 2.7 er. The solution was quenched at 20 C with 9 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 100 ml of EtAc and washed with four 50-mL portions of 0.5 M aq Cl. Concentration of the organic layer to an oil and reconcentration three times from 20-mL portions of EtAc (to remove water) provided 3.98 g of amide 7d (99% yield) as a white solid: 1 MR (400 Mz, d 6 -DMS) δ 9.79 (s, 1), 8.01 (s, 1), 7.96 (app t, J = 1.2 z, 1), 7.02 7.11 (m, 3), 5.14 (dd, J = 6.8, 8.8 z, 1), 2.05 2.20 (m, 2), 2.05 (s, 6), 1.40 1.80 (m, 7), 1.28 (m, 1), 1.14 (m, 1); 13 C MR (100 Mz, d 6 -DMS): δ 167.2, 138.7, 135.0, 134.0, 129.9 (q, J C = 38 z), 127.8, 126.9, 122.1 (q, J C = 265 z), 119.9 (q, J C = 4 z), 59.7, 37.8, 36.4, 31.9, 31.5, 24.7, 24.4, 17.8; RMS-ESI m/z: [M+] + calcd for C 20 24 3 3, 380.1944; found, 380.1943. (S)--benzyl-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)propanamide (7e). A mixture of acid 2 (1.87 g, 6.77 mmol; 98.1 : 1.9 er), benzylamine (0.81 ml, 0.79 g, 7.4 mmol), and pyridine (1.9 ml, 23 mmol) in 3.8 ml of EtAc at 20 C was treated with T3P (8.1 ml, 50 wt% in EtAc, 14 mmol) according to the general procedure. The coupling S-5

proceeded to completion within 22 h at 0 C, and amide 7e was formed in 96.0 : 4.0 er. The solution was quenched at 20 C with 6 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 20 ml of EtAc and washed with two 20-mL portions of 0.5 M aq Cl. Concentration of the organic layer to an oil and reconcentration from 20 ml of EtAc (to remove water) provided 2.43 g of amide 7e (98% yield) as a white solid: 1 MR (400 Mz, d 6 -DMS) δ 8.89 (t, J = 6.0 z, 1), 7.93 (s, 1), 7.89 (app t, J = 1.2 z, 1), 7.29 7.33 (m, 2), 7.21 7.26 (m, 3), 4.94 (dd, J = 6.8, 9.2 z, 1), 4.33 (dd, J = 6.0, 15.2 z, 1), 4.27 (dd, J = 6.0, 15.2 z, 1), 1.98 2.12 (m, 2), 1.36 1.73 (m, 7), 1.15 1.24 (m, 1), 1.02 1.10 (m, 1); 13 C MR (100 Mz, d 6 -DMS): δ 168.6, 138.7, 138.6, 129.8 (q, J C = 38 z), 128.3, 127.3, 127.0, 122.1 (q, J C = 265 z), 119.8 (q, J C = 4 z), 59.6, 42.4, 38.1, 36.2, 31.9, 31.3, 24.6, 24.4; RMS-ESI m/z: [M+] + calcd for C 19 22 3 3, 366.1788; found, 366.1789. (S)--benzyl--methyl-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)- propanamide (7f). A mixture of acid 2 (2.34 g, 8.47 mmol; 98.1 : 1.9 er), -benzylmethylamine (1.2 ml, 1.1 g, 9.3 mmol), and pyridine (2.3 ml, 28 mmol) in 4.7 ml of EtAc at 20 C was treated with T3P (10 ml, 50 wt% in EtAc, 17 mmol) according to the general procedure. The coupling proceeded to completion within 19 h at 0 C, and amide 7f was formed in 97.3 : 2.7 er. The solution was quenched at 20 C with 15 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 100 ml of EtAc and washed with four 50-mL portions of 0.5 M aq Cl. Concentration of the organic layer to an oil and reconcentration three times from 50-mL portions of EtAc (to remove water) provided 3.16 g of amide 7f (98% yield) as a colorless oil: 1 MR (400 Mz, d 6 -DMS) major rotamer: δ 8.03 (s, 1), 7.97 (app t, J = 1.2 z, 1), 7.15 7.41 (m, 5), 5.54 (dd, J = 4.4, 10.8 z, 1), 4.55 (d, J = 14.8 z, 1), 4.48 (d, J = 14.8 z, 1), 3.06 (s, 3), 2.16 (m, 1), 0.90 1.92 (m, 10); minor rotamer: δ 7.91 (s, 1), 7.86 (app t, J = 1.2 z, 1), 7.15 7.41 (m, 5), 5.45 (dd, J = 4.8, 9.6 z, 1), 4.83 (d, J = 16.8 z, 1), 4.73 (d, J = 16.8 z, 1), 2.86 (s, 3), 2.05 (m, 1), 0.90 1.92 (m, 10); 13 C MR (100 Mz, d 6 -DMS): major rotamer: δ 169.0, 139.1, 137.1, 129.8 (q, J C = 38 z), 128.5, 127.6, 126.6, 122.2 (q, J C = 265 z), 120.4 (q, J C = 4 z), 56.1, 50.7, 38.0, 36.4, 34.8, 31.9, 31.4, 24.54, 24.4; minor rotamer: δ 169.2, 138.7, 137.0, 130.0 (q, J C = 38 z), 128.7, 127.5, 127.2, 122.1 (q, J C = 265 z), 119.9 (q, J C = 4 z), 55.4, 52.6, S-6

38.0, 36.1, 34.4, 31.9, 31.4, 24.46, 24.3; RMS-ESI m/z: [M+] + calcd for C 20 24 3 3, 380.1944; found, 380.1943. (S)--isopropyl-3-cyclopentyl-2-(4-(trifluoromethyl)-1-imidazol-1-yl)propanamide (7g). A mixture of acid 2 (2.61 g, 9.45 mmol; 98.1 : 1.9 er), isopropylamine (0.93 ml, 0.64 g, 11 mmol), and pyridine (2.6 ml, 32 mmol) in 5.2 ml of EtAc at 10 C was treated with T3P (11 ml, 50 wt% in EtAc, 18 mmol) according to the general procedure. After 21 h at 0 C, the coupling proceeded to 90% conversion and amide 7g was formed in 93.8 : 6.2 er. The solution was quenched at 20 C with 8 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 50 ml of EtAc, washed with three 30-mL portions of 0.5 M aq Cl, and washed with three 30-mL portions of satd aq ac 3 solution. Concentration of the organic layer and reconcentration from 50 ml of EtAc (to remove water) provided 2.46 g of amide 7g (82% yield) as a white solid: 1 MR (400 Mz, d 6 -DMS) δ 8.27 (d, J = 7.6 z, 1), 7.88 (s, 1), 7.84 (app t, J = 1.2 z, 1), 4.79 (dd, J = 6.4, 9.2 z, 1), 3.80 (d of sept, J = 6.4, 7.6 z, 1), 1.90 2.04 (m, 2), 1.38 1.72 (m, 7), 1.19 (m, 1), 1.07 (d, J = 6.4 z, 3), 1.05 (m, 1), 1.04 (d, J = 6.4 z, 3); 13 C MR (100 Mz, d 6 -DMS): δ 167.5, 138.5, 129.7 (q, J C = 37 z), 122.1 (q, J C = 265 z), 119.8 (q, J C = 4 z), 59.6, 40.9, 38.4, 36.2, 31.9, 31.3, 24.7, 24.4, 22.1, 22.0; RMS-ESI m/z: [M+] + calcd for C 15 22 3 3, 318.1788; found, 318.1787. (R)--phenyl-2-phenylpropanamide (8a). A mixture of (R)-2-phenylpropionic acid (0.20 ml, 0.22 g, 1.5 mmol; >99.9 : 0.1 er), aniline (0.15 ml, 0.15 g, 1.6 mmol), and pyridine (0.22 ml, 2.7 mmol) in 0.5 ml of EtAc at 15 C was treated with T3P (1.7 ml, 50 wt% in EtAc, 2.9 mmol) according to the general procedure. After 20 h at 0 C, the coupling proceeded to 93% conversion and amide 8a was formed without detection of the minor enantiomer. The solution was quenched at 20 C with 2 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 25 ml of EtAc and washed with three 30-mL portions of 0.5 M aq Cl. The organic layer was washed with two 10-mL portions of satd aq ac 3 solution and then 20 ml of water. Concentration of the organic layer and reconcentration three times from 30-mL portions of EtAc (to remove water) provided 0.268 g of amide 8a (81% yield) as an off-white solid: 1 MR (400 Mz, d 6 -DMS) S-7

δ 10.04 (s, 1), 7.57 7.60 (m, 2), 7.37 7.41 (m, 2), 7.21 7.34 (m, 5), 7.01 (m, 1), 3.82 (q, J = 7.2 z, 1), 1.41 (d, J = 7.2 z, 3); 13 C MR (100 Mz, d 6 -DMS): δ 172.2, 141.9, 139.2, 128.6, 128.4, 127.2, 126.7, 123.1, 119.1, 45.9, 18.6; RMS-ESI m/z: [M+] + calcd for C 15 15, 226.1226; found, 226.1227. (R)--benzyl-2-phenylpropanamide (8b). A mixture of (R)-2-phenylpropionic acid (0.20 ml, 0.22 g, 1.5 mmol; >99.9 : 0.1 er), benzylamine (0.18 ml, 0.18 g, 1.7 mmol), and pyridine (0.22 ml, 2.7 mmol) in 0.5 ml of EtAc at 20 C was treated with T3P (1.7 ml, 50 wt% in EtAc, 2.9 mmol) according to the general procedure. After 20 h at 0 C, the coupling proceeded to 96% conversion and amide 8b was formed without detection of the minor enantiomer. The solution was quenched at 20 C with 2 ml of 0.5 M aq Cl solution and warmed to 20 C (amide did not precipitate). The mixture was diluted with 30 ml of EtAc and washed with three 30-mL portions of 0.5 M aq Cl. The organic layer was washed with two 10-mL portions of satd aq ac 3 solution and then 20 ml of water. Concentration of the organic layer and reconcentration three times from 30-mL portions of EtAc (to remove water) provided 0.287 g of amide 8b (82% yield) as an off-white solid: 1 MR (400 Mz, d 6 -DMS) δ 8.46 (t, J = 6.0 z, 1), 7.13 7.35 (m, 10 ), 4.24 (app d, J = 6.0 z, 2), 3.66 (q, J = 7.2 z, 1), 1.35 (d, J = 7.2 z, 3); 13 C MR (100 Mz, d 6 -DMS): δ 173.3, 142.3, 139.5, 128.2 (2C), 127.3, 127.0, 126.7, 126.5, 45.1, 42.0, 18.6; RMS-ESI m/z: [M+] + calcd for C 16 17, 240.1383; found, 240.1387. -Phenyl-( -benzyloxycarbonyl-l-alaninyl)amide (9a). A mixture of -(benzyloxycarbonyl)-l-alanine (5.18 g, 23.2 mmol; >99.9 : 0.1 er), aniline (2.3 ml, 2.4 g, 25 mmol), and pyridine (5.2 ml, 64 mmol) in 10 ml of EtAc at 20 C was treated with T3P (27 ml, 50 wt% in EtAc, 45 mmol) according to the general procedure. The coupling proceeded to completion within 18 h at 0 C, and amide 9a was formed without detection of the minor enantiomer. The solution was quenched at 20 C with 10 ml of 0.5 M aq Cl solution and warmed to 20 C. The precipitated solids were collected on a Buchner funnel, transferred to a clean flask, and reslurried in 70 ml of water for 20 h. iltration of the solids and drying in the vacuum oven at 50 C provided 6.27 g of amide 9a (91% yield) as a white solid: 1 MR (400 Mz, d 6 -DMS) δ 9.99 (s, 1), 7.59 7.63 (m, 3), 7.25 7.37 (m, 6), 7.04 (app t, J = 7.2 z, 1), S-8

5.05 (d, J = 12.8 z, 1), 5.01 (d, J = 12.8 z, 1), 4.20 (dq, J = 7.2, 7.2 z, 1), 1.29 (d, J = 7.2 z, 3); 13 C MR (100 Mz, d 6 -DMS): δ 171.5, 155.8, 139.0, 137.0, 128.7, 128.3, 127.8, 127.7, 123.2, 119.1, 65.4, 50.8, 18.0; RMS-ESI m/z: [M+] + calcd for C 17 18 2 3, 299.1390; found, 299.1390. -Benzyl-( -benzyloxycarbonyl-l-alaninyl)amide (9b). A mixture of -(benzyloxycarbonyl)-l-alanine (5.07 g, 22.7 mmol; >99.9 : 0.1 er), benzylamine (2.7 ml, 2.7 g, 25 mmol), and pyridine (5.2 ml, 64 mmol) in 10 ml of EtAc at 20 C was treated with T3P (15 ml, 50 wt% in EtAc, 25 mmol) according to the general procedure. The coupling proceeded to completion within 20 h at 0 C, and amide 9b was formed without detection of the minor enantiomer. The solution was quenched at 20 C with 15 ml of 0.5 M Cl solution and warmed to 20 C. The precipitated solids were collected on a Buchner funnel, transferred to a clean flask, and reslurried in 70 ml of water for 18 h. iltration of the solids and drying in the vacuum oven at 50 C provided 6.45 g of amide 9b (91% yield) as a white solid: 1 MR (400 Mz, d 6 -DMS) δ 8.40 (t, J = 6.0 z, 1), 7.48 (d, J = 7.6 z, 1), 7.21 7.37 (m, 10), 5.05 (d, J = 12.4 z, 1), 5.01 (d, J = 12.4 z, 1), 4.29 (app d, J = 5.6 z, 2), 4.09 (dq, J = 7.2, 7.2 z, 1), 1.24 (d, J = 7.2 z, 3); 13 C MR (100 Mz, d 6 -DMS): δ 172.5, 155.7, 139.4, 137.0, 128.3, 128.2, 127.77, 127.75, 127.0, 126.7, 65.4, 50.2, 42.0, 18.2; RMS-ESI m/z: [M+] + calcd for C 18 20 2 3, 313.1547; found, 313.1546. -Phenyl-( -benzyloxycarbonyl-l-alaninyl)amide (10). A mixture of -(benzyloxycarbonyl)-l-phenylglycine (2.26 g, 7.92 mmol; >99.9 : 0.1 er), aniline (0.80 ml, 0.82 g, 8.8 mmol), and pyridine (2.3 ml, 28 mmol) in 4.5 ml of EtAc at 20 C was treated with T3P (10 ml, 50 wt% in EtAc, 17 mmol) according to the general procedure. The coupling proceeded to completion within 18 h at 0 C, and amide 10 was formed without detection of the minor enantiomer. The solution was quenched at 20 C with 8 ml of 0.5 M aq Cl solution and warmed to 20 C. The precipitated solids were collected on a Buchner funnel, transferred to a clean flask, and reslurried in 30 ml of water for 24 h. iltration of the solids and drying in the vacuum oven at 50 C provided 2.91 g of white solid containing grains of insoluble material. The soluble material was dissolved in 250 ml of EtAc, passed through a Celite plug, washed with 200 ml of satd aq ac 3, and then washed with 200 ml of water. Concentration of the S-9

organic layer and drying of the residue in the vacuum oven at 50 C provided 2.67 g of amide 10 (94% yield) as a white solid: 1 MR (400 Mz, d 6 -DMS) δ 10.31 (s, 1), 8.13 (d, J = 8.4 z, 1), 7.58 (d, J = 7.6 z, 2), 7.52 (d, J = 6.8 z, 2), 7.27 7.38 (m, 10), 7.05 (app t, J = 7.6 z, 1), 5.44 (d, J = 8.4 z, 1), 5.07 (s, 2); 13 C MR (100 Mz, d 6 -DMS): δ 168.9, 155.9, 138.8, 137.9, 136.9, 128.8, 128.4, 128.3, 127.9, 127.8, 127.7, 127.4, 123.5, 119.2, 65.7, 58.9; RMS-ESI m/z: [M+] + calcd for C 22 20 2 3, 361.1547; found, 361.1549. S-10

Chiral PLC/SC chromatograms of amides 1, 7a g, 8a b, 9a b, 10 (before workup, unless otherwise noted) Amide 1 (in solution before workup) C 3 1 C 2 Bn Amide 1 (isolated) S-11

C 3 7a Me C 3 7b S-12

Me C 3 7c C 3 7d S-13

C 3 7e Me C 3 7f S-14

C 3 7g mixture of 8a enantiomers Me Ph 8a S-15

Me Ph 8b mixture of 8b enantiomers mixture of 9a enantiomers Me Cbz 9a S-16

mixture of 9b enantiomers Me Cbz 9b Ph Cbz 10 mixture of 10 enantiomers S-17

C 3 1 (400 Mz, DMS) o_p-x_00705011_20110510_s2pul_001 12 11 10 9 8 7 6 5 4 3 2 1 0

o_p-04990392_00705011_20110630_s2pul_002 39.510 o_p-04990392_00705011_20110630_s2pul_002 128.514 128.091 134 132 130 128 126 124 122 120 118 116 114 112 168.907 164.109 154.708 149.616 139.651 138.899 135.860 130.448 130.074 126.031 123.377 121.458 120.726 120.116 120.082 112.973 66.310 59.990 36.192 37.512 32.012 30.750 24.605 24.384 128.091 128.514 130.448 130.074 129.696 129.323 126.031 123.377 121.458 120.726 120.116 120.082 120.040 118.076 112.973 176 168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16 8 0

C 3 7a (400 Mz, DMS) o_p-x_00703301_20100713_s2pul_001 11 10 9 8 7 6 5 4 3 2 1 0

o_p-x_00703301_20100712_s2pul_003.esp VerticalScaleactor = 1 39.51 o_p-x_00703301_20100712_s2pul_003.esp 130.44 130.06 129.68 129.31 128.88 126.09 124.03 123.44 120.79 38.07 36.28 120.05 120.01 119.93 119.97 167.39 138.28 138.74 130.44 130.06 129.68 126.09 119.97 123.44 124.03 118.14 60.30 31.99 31.24 24.66 24.48 128.88 130 129 128 127 126 125 124 123 122 121 120 119 118 119.57 119.57 118.14 168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24

Me 7b C 3 (400 Mz, DMS) o_p-x_00703301_20100816_s2pul_001 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0

o_p-x_00703301_20100816_s2pul_002 VerticalScaleactor = 1 o_p-x_00703301_20100816_s2pul_002 39.510 o_p-x_00703301_20100816_s2pul_002 168.115 142.280 138.924 130.202 129.828 129.451 129.073 128.432 126.091 123.444 120.793 120.336 120.298 120.263 118.143 37.790 37.557 35.540 130.122 31.917 30.220 127.677 24.343 24.106 130 128 126 124 122 120 118 38 36 34 32 30 28 26 24 130.202 128.432 130.122 127.677 126.091 123.444 120.793 120.336 120.298 118.143 C 3 56.600 37.790 37.557 35.540 31.917 30.220 24.343 24.106 176 168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16

Me C 3 7c (400 Mz, DMS) o_p-x_00703301_20100812_s2pul_001 10 9 8 7 6 5 4 3 2 1 0

Points Count 65536 Pulse Sequence s2pul Receiver Gain 60.00 Solvent DMS-d6 o_p-x_00703301_20100714_s2pul_001 Spectrum ffset (z) 11013.4375 Spectrum Type STADARD Sweep Width (z) 25125.63 Temperature (degree C) 23.000 o_p-x_00703301_20100714_s2pul_001 VerticalScaleactor = 1 121.106 39.510 o_p-x_00703301_20100714_s2pul_001 121.106 39.510 166.849 155.712 138.676 131.331 113.944 130.400 130.023 129.649 129.271 126.079 123.429 120.778 119.947 119.909 119.870 118.131 38.156 36.253 31.982 31.249 130 129 128 127 126 125 124 123 122 121 120 119 118 40 35 30 C3 129.649 123.429 119.947 119.909 60.211 55.143 36.253 31.982 31.249 24.640 24.468 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10 -20

C 3 7d (400 Mz, DMS) o_p-x_00703301_20100818_s2pul_001 10 9 8 7 6 5 4 3 2 1 0

o_p-x_00703301_20100818_s2pul_002 VerticalScaleactor = 1 o_p-x_00703301_20100818_s2pul_002 o_p-x_00703301_20100818_s2pul_002 39.510 135.042 127.849 3 C 167.158 138.707 134.042 130.133 130.507 126.892 59.658 37.805 36.352 31.890 31.543 24.728 24.419 17.790 126.121 123.471 120.820 119.897 118.169 119.859 130.507 130.133 129.756 129.382 126.121 123.471 120.820 119.897 119.859 119.821 118.169 130.0 129.5 126 125 124 123 122 121 120 119 118 C 3 168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16

C 3 7e (400 Mz, DMS) o_p-x_00703301_20100713_s2pul_001 10 9 8 7 6 5 4 3 2 1 0

o_p-x_00703301_20100713_s2pul_002 VerticalScaleactor = 1 126.079 123.429 120.778 119.863 119.825 119.786 118.131 39.510 o_p-x_00703301_20100713_s2pul_002 42.401 39.510 38.099 36.181 126 125 124 123 122 121 120 119 118 42 41 40 39 38 37 36 128.337 127.284 o_p-x_00703301_20100713_s2pul_002 129.977 129.599 130.351 129.226 130.5 130.0 129.5 129.0 168.565 138.688 138.611 126.995 130.351 129.977 123.429 120.778 119.825 119.786 118.131 59.582 42.401 36.181 31.886 31.291 24.610 24.377 220 200 180 160 140 120 100 80 60 40 20 0-20

o_p-x_00703301_20100901_s2pul_001 Me C 3 7f (400 Mz, DMS) 9 8 7 6 5 4 3 2 1 0

o_p-x_00703301_20100901_s2pul_002.esp VerticalScaleactor o_p-x_00703301_20100901_s2pul_002.esp = 1 o_p-x_00703301_20100901_s2pul_002.esp o_p-x_00703301_20100901_s2pul_002.esp 128.493 127.555 39.510 130.522 o_p-x_00703301_20100901_s2pul_002.esp 169.198 130.332 169.030 169.1 Chem... 130.149 o_p-x_00703301_20100901_s2pul_002.esp o_p-x_00703301_20100901_s2pul_002.esp 139.084 129.958 138.650 138.75 Chemic... 129.771 129.580 130.5 130.0 129.5 137.090 129.397 136.994 129.207 137.10136.95 Chemical S... 128.718 169.030 169.198 127.471 127.231 128 127 126.579 137.090 139.084 127.555 128.493 128.718 130.149 136.994 129.958 126.579 126.190 126.087 123.539 120.889 120.374 120.339 119.901 123.539 123.436 120.889 120.786 120.374 120.339 119.901 119.863 126 124 122 120 118 56.111 118.242 118.139 o_p-x_00703301_20100901_s2pul_002.esp o_p-x_00703301_20100901_s2pul_002.esp o_p-x_00703301_20100901_s2pul_002.esp 56.111 55.421 55.75 Chemi... 52.591 50.688 52.050.5 Chemic... 37.977 36.367 36.062 34.777 34.441 38 37 36 35 55.421 50.688 31.924 31.444 24.541 24.362 36.367 o_p-x_00703301_20100901_s2pul_002.esp o_p-x_00703301_20100901_s2pul_002.esp 31.924 31.444 31.75 Chemic... 24.541 24.457 24.362 24.255 24.5 24.3 Chemical S... 36.062 24.255 C 3 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10 -20

o_p-x_00703301_20100902_s2pul_001 C 3 7g (400 Mz, DMS) 9 8 7 6 5 4 3 2 1 0

o_p-x_00703301_20100902_s2pul_002 VerticalScaleactor = 1 39.510 o_p-x_00703301_20100902_s2pul_002 C 3 C 3 130.252 129.878 129.504 129.130 126.091 36.188 31.894 31.307 24.446 24.663 21.993 22.138 130.252 129.878 129.504 129.130 126.091 123.444 120.793 119.813 119.733 118.143 123.444 138.497 120.793 59.597 119.813 119.775 119.733 40.883 38.366 118.143 130 128 126 124 122 120 118 o_p-x_00703301_20100902_s2pul_002 39.510 167.486 40.883 38.366 36.188 31.894 31.307 24.663 24.446 22.138 21.993 40 38 36 34 32 30 28 26 24 22 176 168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16 8 0

3 C 8a (400 Mz, DMS) o_p-x_00703301_20100729_s2pul_001 10 9 8 7 6 5 4 3 2 1 0

-x_00703301_20100729_s2pul_003 VerticalScaleactor = 1 39.510 C 3 172.169 141.884 139.222 128.646 128.352 126.667 127.242 123.139 119.111 45.932 18.645 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10

3 C 8b (400 Mz, DMS) o_p-x_00703301_20100810_s2pul_001 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0

-x_00703301_20101025_s2pul_002 VerticalScaleactor = 1 126.676 126.489 45.124 42.039 18.591 127.034 127.263 128.201 39.510 o_p-x_00703301_20101025_s2pul_002 128.201 C 3 173.251 142.259 139.517 126.676 126.489 127.263 127.034 128.5 128.0 127.5 127.0 126.5 126.0 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10

3 C 9a (400 Mz, DMS) o_p-x_00703301_20100729_s2pul_001 10 9 8 7 6 5 4 3 2 1 0

-x_00703301_20100729_s2pul_003 VerticalScaleactor = 1 o_p-x_00703301_20100729_s2pul_003 C 3 128.5 128.0 127.5 171.547 155.773 139.016 136.994 128.684 128.329 127.738 123.211 119.146 65.387 50.772 18.046 128.684 128.329 127.788 127.738 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10

3 C 9b (400 Mz, DMS) o_p-x_00703301_20100805_s2pul_001 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0

x_00703301_20100805_s2pul_002 VerticalScaleactor = 1 39.510 o_p-x_00703301_20100805_s2pul_002 172.527 155.705 139.443 137.021 128.318 128.318 128.219 127.769 127.746 126.975 126.667 128.5 128.0 127.5 127.0 126.5 C 3 126.667 126.975 65.375 50.204 41.970 18.240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10

10 (400 Mz, DMS) o_p-x_00703301_20101027_s2pul_001 10 9 8 7 6 5 4 3 2 1 0

-x_00703301_20101027_s2pul_002 VerticalScaleactor = 1 o_p-x_00703301_20101027_s2pul_002 39.510 128.796 168.869 128.445 128.335 155.882 127.873 127.805 127.698 138.766 137.869 136.920 128.796 128.445 128.335 123.537 127.412 119.151 65.654 58.907 127.412 129.0 128.5 128.0 127.5 127.0 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0-10